KK
KK clearly because at least the pair is assured, Instead an AK you have to wait for a pair of those or a high straight that is very difficult to get, in fact I just lost a tournament with AK of clover against a pair of nine , It is frustrating but sometimes the system gives passive players a good hand so that they go all-in and lose in the case of playing online, that's why I prefer a thousand times a pair greater than or equal to 9 than high cards to go all in, but in case I get AK, I just raise the bet, I don't go all-in unless I have few chips as happened to me a moment ago.