BPP MCQ Bank Section A Ques 13

Hi, John.

Sorry to trouble you. The question is as follows:

In material flow cost accounting (MFCA), input manufacturing costs are categorised into material costs, waste treatment costs and which of the following?

A System costs and energy costs
B Positive product costs
C Negative product costs
D Positive products costs and negative product costs

Based on the BPP revision kit, the answer is D

But I read the explanation, not suppose is A?