Final answer:
Cassius's words in the excerpt from Shakespeare's 'Julius Caesar' are meant to convey the necessity of overthrowing Caesar, as he expresses dissatisfaction with Caesar's overwhelming power.
Step-by-step explanation:
In the excerpt from Shakespeare's Julius Caesar, Cassius's lines advance the plot by illustrating D) The need to overthrow Caesar. Cassius uses powerful imagery when he compares Caesar to a colossus, underscoring Caesar's immense influence and how it overshadows other men, including himself and Brutus. This expresses his discontent with Caesar's power and begins to plant the seeds of conspiracy in Brutus’s mind. Cassius’s discontent is reflective of the historical context, where many Romans, particularly the senators, were unnerved by Caesar’s accumulation of power and perceived him as a threat to the Republic.