Answer:
Mindful
Step-by-step explanation:
The most important characteristics of a conversationalist out of these options is the fact that he would be mindful. Being a good conversationalist means that the person is successful at putting people at ease. It also means taht people enjoy talking to this person. It is likely that a good conversationalist would be someone who is mindful, because this would make him aware of whether the other person is enjoying the conversation or not.