KanjiJLPT N4
Answer

solution, answer

Mnemonic

A bamboo tube is carefully carved to fit snugly into a locked chest's keyhole. You slide it in, the lock clicks open, and inside lies a scroll revealing the answer to the ancient riddle. Only the bamboo piece shaped to fit perfectly could unlock the truth.
Additional thoughts
Imagine the satisfying click of bamboo fitting into the keyhole — that tactile 'fit' equals finding the correct answer. Top radical (bamboo) feeds into bottom radical (to fit) just as a key enters a lock.
Quick recall
A bamboo key carved to fit the lock reveals the answer inside.

Details

The keyword for 答 is answer. It refers to a reply or response given to a question, problem, or inquiry. The character conveys the idea of providing a solution or responding to something that has been posed. It is used broadly for both verbal replies in conversation and written solutions to examinations or problems.
On'yomi
とう
Kun'yomi
こた.える、こた.え