Assertion (A): Children who are inattentive find it difficult to sustain mental effort during work or play.

Reason (R): Children with autism spectrum disorder experience profound difficulties in relating to other people.

Both A and R are true, but R is not the correct explanation of A

In assertion statement it is about feature of ADHD and in reason statement it is about autism spectrum, that’s why both are true but R is not correct explanation of A.