You are driving slowly on the highway at 50 mph when a police car with its lights

You are driving slowly on the highway at 50 mph when a police car with its lights flashing passes you going 100 mph. relative to you, the police officer is moving 50 mph. far in the future, when humans have mastered space travel, an astronaut is moving in a spaceship at half the speed of light, v = c/2, relative to earth, when a light beam sent from earth moving parallel to the spaceship passes it moving at v = c. the astronaut measures the light beam to be moving ata. v=2c b. v=c/2 c. v=c d. v=3c/2