The Best Way to Find the Exact Distance to the Moon

Multiple Choice

The best way to find the exact distance to the Moon is to:

A) measure its exact size in the telescope.
B) use radar reflection times, about 2.56 second.
C) bounce lasers off the retroreflectors left on the surface by the Apollo landings.
D) make parallax measurements from observatories on opposite sides of the Earth.
E) use stellar occultations for precise timings of the Moon's position.