Final answer:
Casca informs Cassius that the Senate is conspiring to assassinate Caesar, aligning with historical events where senators plotted to kill Caesar to prevent him from accumulating further power.
Step-by-step explanation:
In Shakespeare's play Julius Caesar, Casca tells Cassius that he has heard about the Senate's plans for the next day. The correct answer to the student's question is that c. The Senate is conspiring to assassinate Caesar. This aligns with the historical context where a group of senators, worried about Caesar's growing power and potential tyranny, conspired to assassinate him on the Ides of March. The assassination plot was led by Brutus and Cassius, who aimed to restore power to the Senate and stop Caesar from possibly declaring himself king, which was against the Republican ideals of Rome.