The words that represent verbs that would be useful in describing the purpose for a text are the following ones: Inform and define.
Cambridge dictionary defines the verbs "to inform" as "to tell someone about particular facts" and "to define" as "to say what the meaning of something is". When you are about to describe the purpose of a text, you are to inform the reader what you want to say and why you are saying it. You are giving meaning to your piece of writing.
First, what is the title and author of the work to which you refer?
The correct answer is that it is a dependent clause.
A dependent clause, as the name itself says, depends on a larger clause in order to make sense. As you can see in the example above, that clause is incomplete - it needs to be part of a larger, independent clause in order to get a proper meaning. The other options are all complete sentences, which is something the example is definitely not.
You need an adverb here, as it will modify the verb, not a noun (or is not a predicate) so the correct answer is "well" - option b.
