Final answer:
Christine is advising Rhoda to forget about something that is bothering her, indicating that she should dismiss it from her thoughts.
Step-by-step explanation:
When Christine advises Rhoda to put it out of your mind, she is suggesting that Rhoda should try to forget about something. This phrase is commonly used in English to indicate that one should stop thinking about a particular issue or concern, often because it is not helpful or beneficial to dwell on it. In the context of the quote, Christine seems to be telling Rhoda that she should dismiss or not concern herself with whatever thought or issue is bothering her. Therefore, the correct answer to the student's question would be: a) Forget about something.