Why Do Astronauts (And Cans of Soft Drink) Float Around

Multiple Choice

Why do astronauts (and cans of soft drink) float around in the Shuttle instead of falling?

A) the Shuttle is so far from the Earth, gravity is negligible
B) the Shuttle's gravity balances the Earth's, so that the net gravity is zero
C) the Shuttle is falling around the Earth (and everything aboard is in free fall)
D) the Shuttle has an antigravity device on board, developed by NASA
E) the rules Newton developed for gravity only hold on Earth, not once you get into space