How is the central idea proven? It's on "The Immigration Contribution" by John F. Kennedy

Titinius.] why didst thou send me forth, brave cassius? did i not meet thy friends, and did not they put on my brows this wreath of victory, and bid me give it thee? didst thou not hear their shouts? alas, thou hast misconstrued everything! but hold thee, take this garland on thy brow. thy brutus bid me give it thee, and i will do his bidding. brutus, come apace, and see how i regarded caius cassius. by your leave, gods,—this is a roman’s part: come, cassius’ sword, and find titinius’ heart. which theme is best expressed by the text evidence in the excerpt? a. power corrupts those who achieve it. b victory has a high cost for both sides of a conflict. c. loyalty to one's superior is more important than life. d.people in power cannot recognize success.