Q. Which of the following event/events produces the “Gravitational Waves”?
1. Colliding black holes.
2. Massive stars exploding at the end of their lifetimes.
3. Super Cyclones.
Select the correct answer using the codes given below:

[A] 1, 2 and 3

[B] 2 and 3 only

[C] 1 and 3 only

[D] 1 and 2 only

Answer: D

The strongest gravitational waves are produced by cataclysmic events such as colliding black holes, supernovae (massive stars exploding at the end of their lifetimes), and colliding neutron stars.  

Other waves are predicted to be caused by the rotation of neutron stars that are not perfect spheres, and possibly even the remnants of gravitational radiation created by the Big Bang. 

Source: NCERT