Which member of the second triumvirate had been a close friend to Caesar?

a. Lepidus

b. Octavian

c. Cassius

d. Antony

I would say Antony my original thought was Marcus Aemilius Lepidus but since that option isn't on there I would go with D) Antony

D. Antony

Explanation:

Mark Antony, Roman politician and general, was an ally of Julius Caesar and the main rival of his successor Octavian (later Augustus). The passing of power between the three men led to Rome's transition from a republic to an empire.