CORRECT ANSWER:
To be able to observe at radio wavelengths
Explanation:
The whole question for the text is
Which of the following is NOT a good reason to place observatories on remote mountain tops?
a- To be able to observe at radio wavelengths
b- To reduce light distortion
c- To reduce light pollution
d- To reduce light absorption
e- To be able to observe at infrared wavelengths
So the correct answer is a- To be able to observe at radio wavelengths
The other options are good reasons