Answer: option C
Explanation:
I choose option c because they are made to fit mating parts easily and do not require further machining.
From the meaning of interchangeable parts, they mean that parts are created almost identical and they would easily fit the same purpose I.e we have part A and B, they are almost I identical . if A does a rotation work and gets faulty part B can easily fit into the part and perform the same work without any other machining.
The best answer that matches my explanation is option C.