Suppose You Wanted to Use Your Radio Telescope to Search

Suppose you wanted to use your radio telescope to search for signals from alien civilizations. Which stars would be the best targets?

A) Low-mass stars, because they are more likely to be old.
B) Luminous stars, because they are the easiest to find in the sky.
C) Nearby stars, because signals would travel to us in the shortest time.
D) Binary stars, because the chances of habitable planets are twice as high.