A 30-Year-Old Woman Takes a Trip on a Rocket, Leaving

A 30-year-old woman takes a trip on a rocket, leaving her 20-year-old brother behind. She travels at a speed of 0.8 c, and is gone 20 years, according to the younger brother. When she returns, how many years older/younger is she than her brother?

A) 2 years younger
B) 2 years older
C) 3 years older
D) 10 years older
E) 8 years older