Which of the following are not electromagnetic waves?

A. Gamma rays
B. Cathode rays
C. X-rays
D. $\beta$-rays
E. Radio waves

Choose the correct answer from the options given below:

B and D only

The correct answer is Option (3) → B and D only

(B) Cathode rays are not oscillating waves because they are made up of particles (electrons) and not oscillating field.

(D) $\beta$-rays are also high-energy, fast-moving electrons or positrons emitted during nuclear decay.