At the same instant, the Sun emits short pulses of red, blue and green light. Each pulse covers the same distance on the way to Mars. Suppose the whole journey takes place through a vacuum. In what sequence would the pulses reach Mars?
- Aall arrive at the same time
- Bblue first, then green, then red
- Cred first, then blue, then green
- Dred first, then green, then blue