Answer:
C. Instructional
Step-by-step explanation:
The style of the given excerpt can be described as instructional. The author mentions instructions often given to the participants of creative writing workshops. He reminds them of what they're not supposed to do - they're not supposed to pile up adjectives.
The meaning of the adjective exuberant is full of energy, excitement, and cheerfulness. There is nothing exuberant about the given passage.
An elegy is a form of poetry that expresses sorrow or lamentation. When something is elegiac, it is related to an elegy in some way. The given excerpt has nothing to do with an elegy.
A text written in the conversational style mimics a conversation. It usually breaks the rules of grammar. As we can see, the given passage doesn't really remind us of a real-life conversation.
This is why the correct option is C.