Answer: C. He angered the Senate by convincing men to serve in wars by promising them land and citizenship.
Step-by-step explanation:
Gauis Marius was such an influential Roman leader that he was granted the title of ''the third founder of Rome'' and his military reorganisation helped move the roman armies from mere militias to professional armies that were loyal to their commanders instead of the Republic.
This last action was key in the transition of Rome from Republic to Empire. Gaius Marius was influential in the Senate and held the Consulship seven times but angered that same Senate when he convinced men to fight in wars with promise of land and citizenship.