Which is probably the best opening??
What can be the best opening is my question
There is no best!
There is simply a FINITE number of good openings and the rest are crap!
The Bongcloud is crap!
The Fried Liver is crap! (For Black - 5...Na5 is TOTALLY EQUAL, 5...Nxd5 is a Blunder!)
The King's Gambit is crap!
The Elephant Gambit is crap!
The Elshad is crap!
Many other openings are crap!
But to say that the Queen's Gambit Declined or Nimzo-Indian or King's Indian or Grunfeld or Queen's Gambit Accepted or Modern Benoni or Slav or Semi-Slav is any better than the others in the list of defenses to Queen Pawn Openings is total nonsense!
Same thing goes for the Big 4 against 1.e4. Anybody that tells you that 1...c5, 1...c6, 1...e5, or 1...e6 is any better than the other 3 options is a total moron!