Answer:
B. "Should the government..."; the answer to this relies on subjective input (what the audience thinks the government should do).
Step-by-step explanation:
Think about the differences between statements that are subjective and objective. If you look at A, C, or D, these results of these experiments are all objective:
A) The amount of electricity generated by a power plant isn't "arguable"; it's a definite value that I can't just "make up" or "think" is correct/valid.
C) The byproducts generated by manufacture aren't "arguable" either; if a byproduct is heat, there's no subjective input.
D) Try to use the above reasoning for D!