Why were tribunes of the plebs so powerful in Roman government?

A. they protected the name of patricians
B. they served as leaders in time of emergency
C. they could veto any law or action of a magistrate
D. they judged important cases

C. they could veto any law or action of a magistrate

Tribunes of the plebs were powerful in Roman government because they had the ability to veto any law or action of a magistrate, including those of the consuls. This power allowed them to protect the interests of the common people (plebeians) and serve as a check on the power of the patrician elite. This made them influential figures in the Roman political system.