Spaceman Speff Orbits Spherical Asteroid X with His Spaceship

Multiple Choice

Spaceman Speff orbits spherical asteroid X with his spaceship. To remain in a circular orbit at 421 km from the asteroid's center, he should maintain a speed of 80 m/s. What is the mass of planet X? (G = 6.67 × 10^-11 N ∙ m²/kg²)

A) 4.0 × 10¹⁹ kg
B) 5.1 × 10¹⁷ kg
C) 4.0 × 10¹⁶ kg
D) 5.1 × 10¹⁴ kg