If you connect with your audience they will want to hear what you say and believe me i have given a few speeches in my life and the only way I could get them not to leave was by doing research with some of them to know what they have come across. And it was successful so I would choose A.
"<span>A. The ease of difficulty with which the subject can be analyzed" would be the best option, since this allows the reader to see which genre "fits" best with the subject or theme in question. </span>
