Best response to Queens Gambit?

I always decline the gambit.

Statistically, here's the answer: https://www.365chess.com/opening.php?m=4&n=23&ms=d4.d5.c4&ns=7.8.23

It looks like C6, E6 and C4 are your options in that order, but they're all pretty much equivalent.

Slav is for more expernieced players, so usually its QG declined.

If it were me, I'd just take the pawn and see what happens. It doesn't occur often enough for me to want to spend time on theory and the statistics support that approach anyway. This might lead me into planned traps but I'll probably learn from these better if I actually lose to them.

I find D4 matches uninteresting. Perhaps I should learn some tricks to make them more interesting. My guess is that there are too many variations on D4 to learn otherwise I'd have seen traps already.