It's got to be C because none of the others relate to collaboration, but I'd say if you were unsure about this answer then the only other sensible one could be B, but I'd go with C.
C. It puts emphasis on the paragraph's main proposal and call to action.
Brutus' tragic flaw of idealism contributes to his downfall because he was gullible enough to be convinced by Cassius and Antony that they were going to murder Julius Caesar for Rome's development and goodwill. He was blinded by that idealism and believed that these were their true intentions for inviting him in the murder, thus, making him involved greatly and made him feel guilty - leading him to suicide.
Which following if ur writing about a company u should start like this
so ans so company id=s known for its good qualitty products
