Riddle

There are several different kinds, but the one you pick doesn't do its job. What is it?

Choose an answer

A.A key
B.A safe
C.A password
D.A lock
Hint: It's a 2-word phrase with 5 letters, starting with "A".

Answer

A lock

Why this is the answer

This is a pun: locks come in many types, but the one skill a thief needs is to 'pick' a lock, defeating its very purpose.

This riddle is filed under "What Am I?" Riddles and rated Hard.