Question

Assertion (A): A black hole is an astronomical entity that cannot be seen by telescope.
Reason (R): The gravitational field on a black hole is so strong that it does not allow even light to escape.

Select the correct answer using the codes given below:
Codes:

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true