Pointing to a photograph, a woman says, "This man's son's sister is my mother-in-law." How is the woman's husband related to the man in the photograph?

Introduction / Context:
This reasoning puzzle involves understanding how the term mother in law connects a woman, her husband and the older generation. The description uses the phrase this man's son's sister to identify the woman's mother in law. You then need to trace how the husband fits into the family tree of the man in the photograph and choose the correct relation term.

Given Data / Assumptions:

• A woman is looking at a photograph of a man.
• She says that the sister of this man's son is her mother in law.
• Mother in law of the woman is the mother of her husband.
• We assume that son and sister here refer to the children of the man in the photograph.

Concept / Approach:
If this man's son's sister is the woman's mother in law, then that sister is a daughter of the man in the photograph. That daughter is the mother of the woman's husband. So the husband is a child of the daughter of the man in the photograph. That makes the husband a grandchild of the man in the photograph. Since the husband is male, the relation of the husband to the man is grandson. The question specifically asks about the relation of the woman's husband to the photographed man, so grandson is the direct answer.

Step-by-Step Solution:
Step 1: Let the man in the photograph be M.Step 2: M has a son. That son has a sister, who is also a child of M.Step 3: The woman says that this sister of M's son is her mother in law. Therefore, that sister is the mother of the woman's husband.Step 4: Since that woman is a child of M and is the mother of the woman's husband, the husband is a grandchild of M.Step 5: The husband is male, so his relation to M is grandson.

Verification / Alternative check:
Draw a tree with M at the top. Under M place two children: one son and one daughter. The daughter is the woman's mother in law. Under this daughter, place the woman's husband. Now trace from the husband up to M: husband to his mother (the daughter of M), and then to his grandfather M. This is exactly the path of a grandson. None of the other described relations, such as son in law or nephew, require this specific two step chain.

Why Other Options Are Wrong:
Son would require the husband to be a direct child of M, but the description clearly inserts the mother in law as the daughter of M.Nephew would require the husband to be the child of M's sibling, not of M's daughter.Son in law would describe someone married to M's child, which is not the case.Cousin implies shared grandparents, not one being directly the grandchild of the other.

Common Pitfalls:
Many learners are tempted to jump straight from mother in law to father in law and incorrectly assume the photographed man is the father in law. However, the puzzle specifically ties the mother in law to being the sister of this man's son, which forces an extra generation. The safest strategy is always to write down each relationship step or sketch a quick diagram before selecting an option.

Final Answer:
The woman's husband is the Grandson of the man in the photograph.