Find the brilliant move by white.

Saw this in an actual game (not mine).  White to move.  Black's last move was pretty amazing in itself - Qb5-Qa4.  Find the highly desired teal colored brilliant reply by white.

Either Rc3 or e6?

(Can't move pieces on the board, and Qxa4 is too simple.)

a8 =Q
Qxa4 gives black the better Q.

Hi Optimissed (love the wordplay in your name!)

I have a low rating and am just starting to really understand moves, etc. I have two questions regarding your answer: 

If white's next move is a8=Q, wouldn't black's next move be Qxa8?

If, as you say,  Qxa4, that would mean black's  Queen is captured, therefore,  black hads no Queen. Right? So how, then,  could black then have a better Queen?

Again,  I'm not even rated half as high as you, so I'm obviously missing something here. Could you please take the time to explain how black would have a better Q if Qxa4?

Thank you so much. 

And, also,  thank you for reminding me to look at EVERY piece before answering a puzzle question. I was so focused on the middle of the board (and, thrown off a bit by the wording of the question ["brilliant teal colored reply"; I don't know this. I thought he meant move to a teal/ blue square])...I missed white's a7 pawn. 

HUGE oversight on my part. No excuse for that besides bad analysis of the board! 

Thank you again! 

Qxc3. If Qxa7 then Qxc2+

Qxc2+ would take 2 moves by the Queen. 

(No disrespect meant. I'm just learning.

I see that it would be impossible for black queen to stop white queen in time to stop check. )

Sorry.

Qxa4 ....c2-c1 queens pawn

Now white's queen is cut off from the play and black's queen on c1 commands the area near white's king.

However, if white plays a7-a8 instead, queening the pawn, white is a queen up and has a won game. Black cannot get near white's king.

nope no one is right .  Chess.com calls the correct move brilliant.  if black gets a queen on C1, he has powerful checkmate options.

So prove the answer I gave, a7-a8 (Q) isn't a win for white.

I think Qxc3 should also win.

OK sorry I saw it. a7 a8 Qxa8 Qxa8 c1 =Q and if Qxd5 then black wins white's Q.

Q x c3 is also wrong due to Rh1, so the correct answer is as 1e41 says

Beg pardon .... was asleep
now to play some blitz and get my blitz grade down by 100.

Yes it is QC1, you can find the actual move in this near perfect game I found recently played by 2 members.  It is move 47 and the player actually found it, pretty impressive.

https://www.chess.com/analysis/game/daily/254470522

ah well

I played some blitz and got my grade down by about 9. definitely not thinking well

Oh. Ok!  Thank you for taking the time to explain that! I see what you mean now. Much appreciated. 😉