What key revision to our understanding has made (at least some of) the icy moons of the outer planets in our Solar System promising targets for searches for life and evidence of past life?

A) We have discovered evidence of organic molecules on the surface of some of the moons.

B) We have discovered that some of the moons likely have liquid water under their surface.

C) We have discovered that the icy moons have been subjected to intense bombardment by comets and meteors.

D) We have discovered that the Jovian planets used to orbit considerably closer to the Sun than they do today.

E) We have discovered that the habitable zone of the Solar System extends beyond the orbit of Saturn.