Through which mode of propagation, the radio waves can be sent from one place to another

Options

A. Ground wave propagation can be sustained at frequencies 500 KHz to 1500 KHz.
B. Sky wave propagation is useful in the range of 30 to 40 MHz.
C. space wave propagation
D. all of them

Answer

D

Explanation

The radio waves can be sent from one place to another through ground wave propagation sky wave propagation and space wave propagation.