A 910-Kg Object Is Released from Rest at an Altitude

Multiple Choice

A 910-kg object is released from rest at an altitude of 1200 km above the north pole of the earth.If we ignore atmospheric friction,with what speed does the object strike the surface of the earth? (G = 6.67 × 10^-11 N ∙ m²/kg²,M_earth = 5.97 × 10²⁴ kg,the polar radius of the earth is 6357 km)

A) 4.5 km/s
B) 2.2 km/s
C) 2.7 km/s
D) 3.2 km/s
E) 4.8 km/s