Take the speed of sound to be 340 m/s. A thunder clap is heard about 3 s after the lightning is seen. The source of both light and sound is:
1) Moving overhead faster than the speed of sound
2) Emitting a much higher frequency than is heard
3) Emitting a much lower frequency than is heard
4) About 1000 m away
5) Much more than 1000 m away