The post office is not far from here.It's only a _ walk.A Five minute B Five-minute C FIve minute

问题描述:

The post office is not far from here.It's only a _ walk.A Five minute B Five-minute C FIve minute
D Five minute

选B,It's only a (five-minute) walk.
这句话也可以这样说It's only five minutes walk. It's only a five minutes' walk.