Choose the exact meaning of the idioms/phrases. Our school is within a stone's throw of the railway station. 

An idiom is a commonly used proverb or statement that has a metaphorical interpretation distinct from its literal meaning. When you say you're "under the weather," you don't necessarily mean that you're standing in the pouring rain, for instance.

A stone's throw away is an expression that means "extremely close." As a result, the correct answer is C) at a short distance.

Very far off refers to something occurring far in the future, in the past, or at a significant distance from the present.
A radius can be either vast or tiny when it's stated as "within a certain radius." It has no end. It can be just two steps away, far away, or however far a bus will carry you.