Pointing to a woman, William said, "Her only sister is the mother of my daughter's mother". How is the woman related to William?

Correct option is D

 Let's break down the statement carefully:

William says, "Her only sister is the mother of my daughter's mother."

• "Her only sister" refers to the sister of the woman in question.

• "The mother of my daughter's mother" refers to the mother of William's wife (since "my daughter's mother" is William's wife).

So, the woman's only sister is William's mother-in-law.

Since the woman is the sister of William's mother-in-law, the woman must be William's wife's sister, i.e., his sister-in-law.

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