It is the main idea of a nonfiction piece of work, or what the author is trying to get out. basically it is the main point of the nonfiction writing
I'd say is a, since the point of a persuasive essay is to give your opinion backed up by research with proof typically, however due to the wording by saying 'references' I don't believe it's b.
Hoped it helped! c:
- Kat
The persuasive technique used in the example given above is emotional appeal because it is trying to connect with the consumers emotions by asking about the cellphone that they are using. By doing that, they are trying to tell the consumer that their product can give a better service than the current product that they own.