Answer:
The children promised <em><u>to </u></em><em><u>be</u></em> back by mine.
the property prices did go up
The correct answer is Carol has a cottage near the shore.
This supporting detail has nothing to do with her study of marine life. She could have this cottage because she inherited it, or she just likes the place - it doesn't really contribute to her love or study of marine life. The other options clearly support why she is studying marine life, whereas the one with the cottage does not.
