County, state, and local committees all choose a chairperson. however, the party s presidential candidate chooses the chairperson at the level.
a. local
b. state
c. county
d. national

The correct answer is D) national.

County, state, and local committees, all choose a chairperson. However, the party´s presidential candidate chooses the chairperson at the national level.

The chairperson is the head of the political party at the three levels: local, state and national. Among its functions, he/she supervise the party operations, the strategy to be used in the election, and leads the fundraising effort. The chairperson has the assistance of staff or party officers to promote the party's platform.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

what words? are you talking about to complet what sentence