How did the actions of Gaius Marius change the Roman Republic?

A: He angered the Senate by proposing that Rome divide public lands among the returning military and their families.
B: He replaced the elected consuls and the Senate with an empire that could be inherited by members of the ruler's family.
C: He angered the Senate by convincing men to serve in wars by promising them land and citizenship.
D: He restructured the city's politics and strengthened the Senate's power.