what is. the best open??

1 e4 and 1 d4 are generally considered best, with 1 c4, 1 Nf3, 1 g3 following.
For black 1 e4 e5 and 1 e4 c5 are generally considered best, with 1 e4 e6, 1 e4 c6, 1 e4 d5 following.
Likewise for black 1 d4 d5 and 1 d4 Nf6 are generally considered best.
It all does not matter that much. You can play any opening without it affecting the result. Games are usually lost by tactical middlegame mistakes, not by choice of opening.

The one you like, that fits your style and that you win more games than you lose when you do use it.
It's usually the d4 or e4, occasionally Nc3 or Nf3 for the first move. Which moves thereafter usually depends on your opponent's move, and your overall plan to attack him/her is contingent on that. This is especially so when a gambit situation occurs, and there is a binary choice of whether to accept it or decline.
Never memorize openings... or maybe do, but don't play a game with the intention of "I must play this opening or that opening". For every move, maximize your options and minimize your weaknesses, and minimize your opponent's options and maximize your opponent's weaknesses.
A good opening will fight for the center with your pawns, put your knights and bishops on active squares, castle your king and connect your rooks. When your a beginner its better to focuses on opening principals then to memorize like 15 moves of theory. Picking an openings is more of a style thing just try a bunch of stuff and follows the opening principals and you will find something that works for you. However if you want to know the opining I like is the queens gambit because it follows all the above rules and I find it pretty intuitive.

There is no such thing. Also, don't just play an opening just because someone says it's the best. If someone knows it better than you then what difference does it make. Also, just because the computer doesn't like an opening doesn't mean you can't win with it. The Stafford is a dubious opening that can be refuted if played correctly, but most people (especially in blitz or bullet) don't know how to refute it and get mated easily

Chess Openings Tier Lists by GM Hikaru Nakumura and IM Levy Rozman
Chess openings are rated in terms of their appropriateness vis-a-vis player skill level - i.e., beginner vs intermediate vs GM’s, etc. For each of the openings discussed be sure to pay attention to whether the evaluation is from White’s or Black’s perspective. They also frequently refer to some openings as "garbage" or "bad"; these qualifiers are used in the context of, for example, how much so-called "theory" (i.e., documented variations) the opening encompasses, or how much emphasis the opening places on positional versus tactical skills in order to play it well. For example, an opening they refer to as "garbage" (an unfortunate choice of terms) for a beginner may in fact be appropriate for higher rated players who typically know more of the theory for particular openings and have a more highly developed understanding of positional concepts.
The Chess Openings Tier List for Beginners…
https://www.youtube.com/watch?v=M9CwH47r6og
https://www.youtube.com/watch?v=fHsb7-LbC34
https://www.youtube.com/watch?v=z3FBRlzSMHc
The Chess Openings Tier List for Intermediate players...
https://www.youtube.com/watch?v=Qq_rEYTiLy4
https://www.youtube.com/watch?v=mCVdrmKHdiI
https://www.youtube.com/watch?v=Pblb8ZQ3OJ4
The Chess Openings Tier List for GM's...
https://www.youtube.com/watch?v=glMp0dNGPN4
https://www.youtube.com/watch?v=3vzDjlu-96s
https://www.youtube.com/watch?v=HShiBcGbfeA
The Chess GAMBITS Tier List for Beginners...
https://www.youtube.com/watch?v=S9N6Bo7BBPg
GAMBITS.....with moves...
https://www.angelfire.com/nf/chess/Gambits.html
https://en.wikipedia.org/wiki/List_of_chess_gambits
https://www.mark-weeks.com/aboutcom/aa04g10.htm
https://www.mark-weeks.com/aboutcom/aa04g31.htm
https://www.ianchessgambits.com/
Openings Guides - SimplifyChess.com...
https://simplifychess.com/homepage/openings.html
Chess Openings Resources for Beginners and Beyond...
https://www.chess.com/blog/RussBell/openings-resources-for-beginners-and-beyond
https://www.chess.com/blog/RussBell

Hi! My name is Lauren Goodkind and I’m a chess coach and chess YouTuber based in California:
https://www.youtube.com/channel/UCP5SPSG_sWSYPjqJYMNwL_Q
Everybody has their own preference, so one needs to just explore different openings to determine which one is the best. I love to play e4, but some people do not. I highly recommend beginners to play e4 or d4 to get at least one pawn in the center.