Final answer:
The synonym for 'incendiary' that provoked a riot is 'instigative,' with 'inciting' as an alternative synonym. 'Aggressive' can be related but is not as specific, while 'peaceful' is the antonym and not a synonym.
Step-by-step explanation:
The speaker was not invited back because his incendiary behavior caused a riot. Among the options provided, the synonym for incendiary is instigative, which is option 1. It best captures the essence of a behavior that provokes or stirs up trouble or conflict. Option 2, inciting, is also a fitting synonym and could be an alternative correct response, as it similarly means to stir up, urge on, or provoke. Aggressive, option 3, might somewhat relate in that aggressive behaviors can be incendiary, but it is not the best synonym as it lacks the specific implication of provoking unrest or violence. Option 4, peaceful, is the antonym of incendiary, so it does not apply in this context.