Answer:
The correct option is letter D. Mark Antony helped to calm the volatile audience members.
Step-by-step explanation:
In this sentence, we can see how the antonym clue is "to calm", which helps us understand that "volatile" is the opposite. Antonyms are words with opposite meanings. Some examples would be:
"Angelo cleaned the dirty kitchen by himself"
"Mark is very quiet; unlike his noisy, crazy family."