Choose the best tool to open lock (4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Quadruple definition! To select one of a range of options; the best among multiple items, as in “the pick of the crop”; a tool (also called a pickaxe) for breaking up soil and dislodging rocks; or to use tools other than the intended key to break open a lock.