What Is the Main Reason for Using Several Radio Telescopes

Multiple Choice

What is the main reason for using several radio telescopes together as an interferometer?

A) to obtain much better angular resolution or sharpness in the images
B) to ensure that at least one of the telescopes is in a radio-interference-free zone
C) to collect more radiation from very faint sources
D) to ensure that observations are uninterrupted by the failure of one or two telescopes