The answer would be B. 16/2704.
Explanation: the probability of choosing a six the first time is 4/52 (since there are 4 sixes in a pile of 52 cards). Since you put the card back in the pile, the chances of drawing a six are 4/52. Remember that AND means multiplication and OR means addition when dealing with probability. Because of this, we then multiply the two together to show the chances of these both happening to have
4/52 * 4/52 = 16/2704