A
Explanation: pigeon hole principle states that, if we have n objects & m boxes s.t. #objects > #boxes & we are required to put ever object in a box, then at least 1 box will contain more than 2 objects.
this same principle applies for pumping lemma in a bit different form.
if a string of length n need to be accepted by a FA then it require at least n+1 states. Now if this string have some part repeating then we may have to apply loop on at least 1 state.