City council member: Demand for electricity has been increasing by 1.5 percent a
year, and there simply is no more space to build additional power plants to meet
future demand increases. We must therefore begin to curtail usage, which is why I
propose passing ordinances requiring energy-conservation measures in all city
departments.
The city council member’s proposal assumes which of the following?
(A) Existing power plants do not have the capacity to handle all of the
projected increase in demand for electricity.
(B) No city departments have implemented energy-conservation measures
voluntarily.
(C) Passing ordinances designed to curtail electricity usage will not have
negative economic consequences for the city.
(D) Residential consumers are not responsible for the recent increases in
demand for electricity.
(E) City departments that successfully conserve energy will set a good
example for residential and industrial consumers of electricity.
OA is A.

The question stem clearly states that the council specifically mentions passing energy conservation ordinance in city departments. Then why is option D wrong ? If residential consumers are responsible, then this argument breaks. By using negation, D seems to be the right answer choice.