Final answer:
The correct answer to the student's question is 'squirrel,' referring to the animal and the idiom 'squirrel away' that means to hide valuables.
Step-by-step explanation:
The arboreal rodent whose name can also mean to hide something away, such as money, is the squirrel. This term not only refers to the small, nimble animal that climbs trees but also to the action of hiding valuables, often for later use. In the context of this question, option A) Squirrel would be the correct answer, with 'squirrel away' being the associated idiom referring to the act of hoarding or saving something, often money.