Answer:
D. all of the above.
Step-by-step explanation:
All of the above are important for being a good conversationalist because, one must be a good listener if the want to be able to keep up with conversations, especially if they are fast paced, and having a good vocabulary is good for that too, because you need to know how to properly speak, to stay in a conversation, and being a eloquent speaker is good too because you wouldnt want to stumble over your own words or so.