Which statement about the inner and outer planets is true

The correct answer is - The inner planets revolve and rotate faster than the outer planets.
The inner planets are much smaller and they rotate around their axis much faster than the outer planets that are much bigger and rotate slower. 
The inner planets also revolve around the Sun much faster cause they are much closer to the Sun, so the Sun's gravitational pull has bigger effect on them, while the outer planets are much further from the Sun, it's gravitational pull has smaller effect on them, and their track around it is much bigger.

Sonar is an application of the doppler effect used by submarines.  this test was on k12.