Starship Enterprise is in a circular orbit of period 300 minutes around planet Thera at an altitude of 1000 km. A Klingon spaceship then enters another circular orbit around Thera at an altitude of 19000 km. Thera has a radius of 5000 km. The Klingon spaceship circles Thera in
(a) 600 minutes.
(b) 1200 minutes.
(c) 1800 minutes.
(d) 2400 minutes.