Because of the Electoral College, presidential candidates generally spend most of their time and resources in:
A. California, Texas, and New York, which have the largest populations.
B. states where they have a comfortable lead, in order to extend that lead.
C. swing states that have a lot of electoral college votes.
D. states where there are competitive local races so that they 'coattail' to a win.
E. Washington D.C. to demonstrate how 'presidential' they are.
In our system, if a presidential candidate is certainly going to win a state (for example, Republicans in Idaho or Democrats in Washington), there is no need for them to campaign in that state. It will not help them to win by a larger margin. Conversely, they will not campaign in a state they are sure to lose because it does not help them to lose by a smaller margin. Therefore, they will want to go and campaign in states where they are not guaranteed to win or to lose. These are the “swing states.” If they are going to campaign in swing states, they will pay the most attention to states with many electoral votes because those are the states that are more valuable. Therefore, option C is the best answer.
As for Option D, we usually say that state and local candidates “coattail” on presidential candidates, not the other way around. Therefore, a presidential candidate would not be likely to try to coattail on a local candidate.