Pointing to a photograph, a lady tells Sohan, "I am the only daughter of this woman, and her son is your maternal uncle." How is the lady related to Sohan's father?

Wife

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: