None of the choices is correct.
== The Earth's radius is 6,371 km. That's how far you are from the center of the Earth when you're on the ground.
== The acceleration of gravity on the ground is 9.8 m/s² .
== The acceleration of gravity varies inversely as the square of the distance from the center of the Earth. So, at 7,200 km from the center, it's
(9.8 m/s²) · (6371km/7200km)² .
Stuffing this through your cakulator, you'll get 7.67 m/s² .