What Important Theory of Physics Did Werner Heisenberg Propose

What important theory of physics did Werner Heisenberg propose?

A) the "uncertainty principle," demonstrating that it was impossible to measure both the position and speed of an object
B) the earliest explanation of what Einstein later developed into the theory of relativity
C) a mathematical proof of physics indicating that the universe had defined limits
D) the nuclear structure of atoms that might then be split into their component parts
E) the theory that light was emitted in short, independent units he labeled as "quantum"