If We Wanted to Search the Milky Way for Other

If we wanted to search the Milky Way for other civilizations, where should we look?

A) near high-mass stars, because they live longer
B) near low-mass stars, because their habitable zones are farther from their stars
C) near the galactic center, because the higher temperature makes life more likely
D) in the disk of the Milky Way, because planets there are more protected from harmful gamma rays and X-rays coming from the galactic center
E) in the halo of the Milky Way, because stars in the halo have more heavy elements than stars in the disk