Please help with this question 20 points!! "Certain social classes changed in the transition from the Roman Republic to the Roman Empire."

Which of these supports this statement? (4 points)

Select one:
a. Marcus Aurelius promoted army officers based on merit, rather than their social standing.
b. Hadrian put an end to Rome's territorial expansion.
c. Trajan led an extensive public building program in Rome.
d. Diocletian established a tetrarchy to deal with "the Crisis of the Third Century."