please help me with this

5. at a given time, Saturn was 9.1 × 10^8 miles from the Sun and Earth was 9.3 × 10^7 miles from the Sun. by what distance is one planet closer to the Sun than the other?

A) 2 × 10^1
B) 2 × 10^15
C) 8.17 × 10^7
D) 8.17 × 10^8