The correct answer is B. Every year, we bought a homemade apple pie that cost only $5 at a little store on the road to the cabin.
Explanation:
In the sentences presented the section "that cost only $5" is a modifier because this describes the noun "homemade apple pie". Moreover, this modifier should be placed right after the noun it describes to clarify the "$5" refer to the cost of the pie.
This occurs in option B "a homemade apple pie that cost only $5" because this places the modifier after the noun, and this makes the sentence to be clear. On the other hand, in other options the meaning is confusing. For example in A "a homemade apple pie at a little store that cost only $5," it is not clear if the cost refers to the apple or the store.
