The fact that many middle-class and lower-middle-class citizens who did not stand to benefit from president george w. bush's tax cuts seemed to favor them is an example of the a. importance of political efficacy. b. importance of self-interest. c. importance of political knowledge. d. "spiral of silence."

This is an example of C. importance of political knowledge.
These people didn't know enough about politics and the politicians they were voting for which is evident based on this question. They favored some politicians because they were gullible and didn't understand that favoring them won't really give them any benefits. If they had more knowledge, they would probably have voted for a better candidate. 

Bthreatening to ally with germany