What Recent Series of Discoveries Has Made Astronomers More Optimistic

What recent series of discoveries has made astronomers more optimistic about our prospects of finding life out there?

A) the discovery of a form of silicon-based life in the volcanic vents of Venus
B) the discovery of planets around thousands of stars in our Galaxy
C) the discovery of a black hole approaching our solar system at rapid speed
D) the discovery of many key building blocks of life in a crater near the polar region of the Moon
E) the discovery of a spaceship, built by an alien civilization, that crashed in New Mexico