Introducing a girl, Vipin said, "Her mother is the only daughter of my mother-in-law". How is Vipin related to that girl?

Family tree

Let's break down the statement:

"Her mother is the only daughter of my mother-in-law."

• My mother-in-law: This refers to Vipin's mother-in-law.
• Only daughter of my mother-in-law: This means Vipin's wife.
• Her mother is ... Vipin's wife: This means the girl's mother is Vipin's wife.

Therefore, Vipin is the father of that girl.

Hence, the correct answer is "Option 2".