A console lamp in the cabin of a spaceship appears green whe

A console lamp in the cabin of a spaceship appears green when the ship and observer are both at rest. When the ship is moving at 0.90c away from Earth, passengers on board see: a) a dark lamp (the frequency is too high to be seen) b) a dark lamp (the frequency is too low to bo seen) c) a red lamp d) a violet lamp e) a green lamp

c)red lamp