Why Was the Galileo Spacecraft NOT Just Left Floating in Space

Multiple Choice

Why was the Galileo spacecraft NOT just left floating in space when its mission ended?

A) The last part of the mission was a final probe of Jupiter's atmosphere.
B) It was feared that Galileo might someday crash on Europa and contaminate its oceans with biological organisms from Earth.
C) It was feared that the new Cassini spacecraft might crash into it.
D) Galileo carried a nuclear reactor, and the spacecraft was destroyed to prevent possible radioactive contamination.