There Are Now Over 3700 Known Extrasolar Planets

There are now over 3700 known extrasolar planets. When astronomers consider them as possible homes for life, it is important to remember that MOST of them are

A) Earthlike planets with water on their surfaces.
B) hydrogen-rich planets like Jupiter.
C) in extremely elliptical orbits, like comets.
D) still in the process of forming and thus not old enough to have evolved life.