Answer:
Step-by-step explanation:
The third one done is the answer I would choose. If you want to cite something, you need the act (which is given), the scene (which is not given), and the line number (also not given).
We do know where it occurred and under what circumstances. Caesar has just been murdered and Brutus has given us a fine speech about the circumstances of his death.
This line is the first line of Mark Antony's rebuttal.