Introducing a man to her husband, a woman said, “His brother’s father is the only son of my grandfather.” How is the woman related to this man?

Here is a diagram to illustrate the relationship:

[Diagram of a family tree showing the woman, her husband, and the man]

The woman’s grandfather is the man’s great-grandfather. The woman’s husband is the man’s first cousin once removed. The man is the woman’s first cousin.

Here is a brief explanation of each option:

• A. Mother. The woman is not the man’s mother because the man’s father is the woman’s grandfather’s only son.
• B. Aunt. The woman is not the man’s aunt because the man’s father is the woman’s grandfather’s only son.
• C. Sister. The woman is the man’s sister because the man is the woman’s cousin.
• D. Uncle. The woman is not the man’s uncle because the man’s father is the woman’s grandfather’s only son.
• E. Nephew. The woman is not the man’s nephew because the man is the woman’s cousin.