@Crystal not sure I am understanding your question here since water temperature is not mentioned in the stimulus.
This stimulus is about temperate zones and the tropics.
If you are referring to (A), it is incorrect precisely for this reason.
Knowing the answer to (A) would not be helpful in determining whether what the scientist subsequently learned regarding migratory fish in the tropics would call the scientist's hypothesis into question.
Hope this helps! Please let us know if you have any other questions.
