The captain of a spaceship orbiting planet X discovers that to remain in orbit at 410 km from the planet's center, she needs to maintain a speed of 68 m/s. What is the mass of planet X?
A) 2.8×10⁶ kg
B) 2.8×101⁹ kg
C) 4.2×10¹⁷ kg
D) 4.2×10¹⁴ kg
E) 6.7×10¹⁸ kg
