Given below are two statements: 

Assertion (A): Though the central atom of both NH3 and H2O molecules are sp3 hybridised, yet H-N-H bond angle is greater than that of H-O-H.
Reason (R): This is because nitrogen atom has one lone pair and oxygen atom has two lone pairs.

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.
Assertion and reason both are correct and reason is the correct explanation of assertion.