Here's my approach (downvote if wrong):

falling on outstretched arm → usually scaphoid

BUT

scaphoid problem → pain in anatomical snuffbox

so then it goes to the next most commonly injured bone when you fall on an outstretched arm, your lunate

(which is right next to the scaphoid)

Capitate and lunate are in the center of the palm. Capitate is not an option, so lunate is the answer.

Dislocation of lunate may cause acute carpal tunnel syndrome.

FOOSH (Fall on outstretched hand):

Most common fracture = scaphoid Most common dislocation = lunate

According to Boards and Beyond ： lunate attached to radius.

falling in outstretched hand, other bones forced backwards when lunate displaced toward palm/ So in this position ,lunate dislocation is most common