A Rocket of Length 80 M Sits on a Launch

Multiple Choice

A rocket of length 80 m sits on a launch pad in outer space. The center of mass of the combined rocket and launch pad system is located in the center of the launch pad. The rocket is launched and reaches a distance of 100,000 km from the starting position. Where is the location of the center of mass of the total rocket-fuel-launch pad system then?

A) at the center of the launch pad
B) at the starting position
C) 100,000 km from the launch pad
D) 80 m from the launch pad
E) 50,000 km from the launch pad