Q: You are given a sentence, a question and two answer options ('A' and 'B'). Your task is to find the correct answer (return the string of the correct option, not 'A' or 'B') for the given question.
Sentence: An astronomer was studying the properties of some stars. She saw that one was a neutron star that was so densely packed with material that it had a far larger mass than an ordinary star that she was also observing. Question: Which of these stars would she expect to have a greater gravitational force? (A) neutron star (B) ordinary star
A:
neutron star