If a child is a back bencher and unable to watch the blackboard clearly. As a result he stands, sees and sits repeatedly. What inference will you draw regarding the case?

The correct answer is D. Both (a) and (c).

The child is a back bencher and unable to watch the blackboard clearly. This could be due to two reasons:

1. The child is of short height as compared to his classmates. This means that the blackboard is too high for him to see clearly from his seat.
2. The child has a defective-vision. This means that he cannot see clearly even if the blackboard is at a lower height.

In either case, the child will stand up to see the blackboard clearly. This is because standing up will allow him to see over the heads of his classmates.

It is also possible that both reasons are true. In this case, the child will stand up to see the blackboard clearly, but he will still have difficulty seeing even when he is standing.

If you are a teacher, you can help the child by:

1. Arranging the classroom so that the child can sit in the front row.
2. Providing the child with a raised seat.
3. Referring the child to an eye doctor.