What was the relationship between the senate and the magistrates in the roman republic?

a. the senate ruled over the magistrates.

b. the senate advised the magistrates.

c. the magistrates appointed senators.

d. the magistrates elected senators.

Correct answer is answer C, Magistrates could appoint Senators.  

Explanation:

Magistrates appointed Senators.  Senators were elected by Consuls, Tribunes and Censors.  But Magistrates could select Senators that, as in the case of an election by Censor, did not have the right to vote.  Even though Senators could have been appointed by Magistrates (answer C), those did not have the power to elect them (answer D)

Senators were a deliberative organ, while Magistrates were a legislative organ.  This means that Magistrates created law, and Senators were a political authority in the representation of the whole Roman Empire, having the power to move the military into war or construct new infrastructure. Therefore, this explanation indicates that Senators did not rule over the Magistrates (answer A) or adviced the Magistrates (answer B).