Pointing to a photograph of a man, Pooja said, "He is the only son of the mother of my sister's brother." How is that person related to Pooja?

None of these

Before answering this question we must be aware of the method to solve the blood relation questions.

For example : 

It is now clear, how to make charts in Blood relations. Now, shifting to another type, in this we solve the question in the following manner.

The chart for the above question is as follows: