A good way to know whether there is an infinitive is to see whether there is the word "to" in the sentence.
So b. and c. are good candidates.
in C. however to is not part of the verbal phrase:
so the correct answer is b: and the infinitive is <span>to listen</span>
The safest type of medical treatment would be one run by a doctor at a clinic.
Writer
The byline appears at the top of the page and is usually the second line of an article, after the title and before the text of the article, letting the reader know who wrote the piece. It's an important factor to consider when designing the layout of a page.
