Radioactive Muons Formed High in the Atmosphere Have an Average

Multiple Choice

Radioactive muons formed high in the atmosphere have an average lifetime of 2 millionths of a second and travel toward Earth at nearly the speed of light. Because of their altitude most of them should have decayed by the time they reach the Earth's surface, according to pre-relativity physics. They don't because they

A) live longer due to time dilation.
B) travel a shorter distance due to length contraction.
C) both of these
D) neither of these