Pointing to a man, Manisha said, "He is the youngest son of my father in law's only son". How is manisha related to this youngest sons' father?

a) daughter

b) sister

c) wife

d) cant be determined

Looking at it from Manisha's perspective, "my father-in-law's only son" would be my husband. Thus the youngest son of this person would also be Manisha's son. hence the person's father would be Manisha's husband and Manisha would be the wife.