Pointing to the photograph of a lady, Sukanya said, "Her son's son is the brother of my daughter's sister." How is the lady related to Sukanya?

Mother-in-law

ATQ,

*********************************************************

Please note:

  l   ⇒ Vertical line shown "generation gap".

 =  ⇒ Double lines shown "relation of spouse" 

—  ⇒ Horizontal line shown "relation in same generation other than spouse".

     ⇒ Rectangular box shown " Male".

     ⇒ Circular box shown " Female".

*********************************************************