A woman says, "My husband's father is the only son of your grandfather." How is the woman's husband related to you, assuming your grandfather's only son is your father?

Answer: C. brother

The woman's husband's father is the only son of your grandfather. Since the question states that your grandfather's only son is your father, the woman's husband's father must be your father. Therefore, the woman's husband is your father's son, which means he is your brother (assuming he is not you). Hence, the correct answer is A) Brother.

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