Critical Reasoning

Hi,

Would you please explain the difference between subsidiary conclusion and reasoning's contention?

"The amount of energy used by a typical household in the northeastern United States is more than twice that used by a comparable household in southeast, southwest, and west coast regions of the country". The difference is explained by the heating requirements of homes in the northeast. In general air conditioners used to cool homes are much cheaper to operate than heating systems. Up to 65% of the total energy usage of a household in the northeastern U.S. is required to heat the home through the winter: only 5% is needed for air conditioning throughout the whole summer. However, global warming is changing the equation. "Winters in the northeast are getting warmer, requiring less heat per day and shortening the heating season." Temperatures in the across the U.S. are getting hotter so that the cost of cooling homes is rising. In years to come the energy requirements across the country will be far more uniform.
The portions in boldface play which of the following roles?
A) The first is a subsidiary conclusion of the argument that is used as a premise to support the main conclusion; the second is a fact that directly contradicts the first.
B) The first is a paradox that must be resolved later in the argument; the second is the key evidence used to resolve that paradox.
C) The first is a fact that is directly contradicted later in the argument; the second is the evidence used for that contradiction.
D) The first is a fact that the argument explains and then predicts will not hold true over time; the second is used as evidence that the first fact will change.
E) The first is a phenomenon that contributes to the explanation of another phenomenon discussed later in the argument; the second is the phenomenon that the argument explains.