Question

Radio spectrum is the part of the complete range of electromagnetic waves that is used for radio communication from

1 kHz to 100 GHz.
2 kHz to 200 GHz.
3 kHz to 300 GHz.
4 kHz to 400 GHz.

Answer 1

Radio spectrum is the part of the electromagnetic spectrum ranging from 1 Hz to 3000 GHz.

Radio waves are EM (Electromagnetic)waves that have wavelengths between 1 millimeter and 100 kilometers (or 300 GHz and 3 kHz in frequency).

So I'm thinking the answer might be 3 kHz to 300 GHz.