Pointing to the lady in the photograph, Seema said, 'Her son's father is the son-in-law of my mother.' How is Seema related to the lady?

Introduction / Context:
This question is a slightly tricky blood relation puzzle involving a photograph, a son's father and the phrase son-in-law of my mother. Seema must determine how she is related to the lady in the photograph. The crucial observation is that my mother's son-in-law is the husband of one of her daughters, which in a simple family structure is normally interpreted as the speaker's own husband. From there, you can see how the lady fits in.

Given Data / Assumptions:
- Speaker: Seema. - There is a lady in the photograph. - The lady has a son; his father is the lady's husband. - The son's father is described as the son-in-law of Seema's mother. - The usual exam assumption is that my mother's son-in-law refers to the husband of the speaker (if no sisters are mentioned).

Concept / Approach:
Let us call the lady L and her husband H. L's son's father is H. The statement says H is the son-in-law of Seema's mother, meaning H is married to one of Seema's mother's daughters. In a minimal family, the only such daughter mentioned is Seema herself, so H is Seema's husband. If L's husband is Seema's husband, then L and Seema are both married to the same man, which is not the usual intended exam interpretation. Instead, the standard reading is that the lady herself is Seema or, more naturally here, that the lady is Seema's sister, whose husband is also a son-in-law of Seema's mother. However, a son-in-law of my mother can be the husband of any of her daughters, including Seema's sister. In that more natural reading, L is Seema's sister.

Step-by-Step Solution:
Step 1: Let the lady in the photograph be L. Her son's father is her husband H. Step 2: The statement Her son's father is the son-in-law of my mother means H is a son-in-law of Seema's mother. A son-in-law of Seema's mother is the husband of any of her daughters. Step 3: Seema is one daughter of her mother. It is also possible that Seema has at least one sister. In that case, the husband of Seema's sister is also a son-in-law of Seema's mother. Step 4: In the intended standard reasoning, we avoid polygamous scenarios. Instead of assuming H is married to both Seema and the lady, we take H as the husband of Seema's sister. Then the lady L is that sister. Step 5: Therefore, from Seema's perspective, the lady in the photograph is her sister.

Verification / Alternative check:
Construct a family where Seema's mother has two daughters: Seema and her sister L. L is married to H, and they have a son. For the son, H is the father. From Seema's mother's viewpoint, H is the husband of her daughter L, so H is indeed a son-in-law. This matches Seema's description that the lady's son's father is the son-in-law of my mother. In this clean and consistent setup, L is unambiguously Seema's sister.

Why Other Options Are Wrong:
- Mother: If L were Seema's mother, then L's husband would be Seema's father, who is not normally described as son-in-law of my mother but as her husband. - Cousin: No cousins or siblings of Seema's mother are mentioned; the relation runs directly through daughters and their husbands. - Aunt: An aunt would be a sister of Seema's mother or the wife of her brother. That does not match the description of the husband being my mother's son-in-law. - Daughter: For L to be Seema's daughter, the son's father would be Seema's son-in-law, not Seema's mother's son-in-law.

Common Pitfalls:
The main pitfall is to assume that my mother's son-in-law must be my own husband, leading to an unrealistic interpretation where Seema and the lady share a husband. Verbal reasoning questions typically avoid such complications and instead imply that a son-in-law can be married to any daughter, including a sister of the speaker. Keeping this in mind, and remembering that someone whose husband is a son-in-law of your mother is likely your sister, leads to the correct answer.

Final Answer:
Seema is related to the lady in the photograph as her sister.