Answer:
a and b.
Explanation:
In general types of wave
1. Transverse wave :
In these waves particle are vibrate perpendicular to motion of waves.
Ex : Electromagnetic wave , Radio wave .
2. Longitudinal wave :
In these waves particle are vibrate along the motion of waves.
Ex : Sound wave
Mechanical wave :
1 .These are transverse wave or Longitudinal wave or combination of them .
2.These waves required medium for propagation.
3. The particle are vibrate perpendicular to motion of waves.
So the option a and b are correct.