Neena told Deepali that, "your mother-in-law is my father's granddaughter's father's grandfather's daughter-in-law''. How is Deepali related to Neena ?

Neena told Deepali that the mother-in-law of Deepali is Neena's father's granddaughter's father's grandfather's daughter-in-law.

Neena's father's granddaughter means that there is a person who is the daughter of either Neena or her sibling. Father of the granddaughter means that he is the husband of either Neena or her sibling. 

Now, daughter-in-law of the Grandfather of the husband means the mother of the husband of Neena or her sibling i.e. mother-in-law. It means that the mother-in-law mentioned in the question is the mother-in-law of either Neena or her sibling. 

But, it is mentioned that the mother-in-law in this question is for Deepali. 

Hence, Deepali is the sister of Neena. 

Option A.