A man says to a lady, "Your mother's husband's sister is my aunt." In this standard blood relation test question, how is the lady related to the man?

Introduction / Context:
This blood relation question requires careful decoding of a layered description. A man describes a woman related to the lady as my aunt. We must unwind expressions such as your mother's husband's sister and then connect that person to the speaker. Finally we must infer how the lady herself is related to the man. These types of questions are typical in competitive exams and demand a clear visualization of the family tree.

Given Data / Assumptions:
• The man is speaking to a lady.• He says that "your mother's husband's sister is my aunt."• Your mother's husband is the lady's father.• The sister of the lady's father is the lady's paternal aunt.• The same woman is called my aunt by the man, meaning she is a sister of one of his parents.• We assume a normal family structure with no hidden adoptions or remarriages.

Concept / Approach:
The key person in the puzzle is the woman who is both the sister of the lady's father and the man's aunt. If this woman is the sister of the man's father, then the man's father and the lady's father are brothers. That means the man and the lady are children of two brothers, which makes them first cousins. This is the simplest and most natural configuration that satisfies the given sentence completely.

Step-by-Step Solution:
Step 1: Your mother's husband is the lady's father.Step 2: The sister of the lady's father is the lady's paternal aunt. Let us call this aunt X.Step 3: The man says that X is my aunt. That means X is the sister of either the man's father or the man's mother.Step 4: The simplest and most consistent assumption is that X is the sister of the man's father. Then the man's father and the lady's father are brothers.Step 5: If the lady's father and the man's father are brothers, the lady and the man are children of two brothers and therefore first cousins.Step 6: Hence the lady is the cousin of the man.

Verification / Alternative Check:
Imagine grandparents who have two sons, F1 and F2, and a daughter X. Let F1 be the man's father and F2 be the lady's father. X is the sister of F2 and therefore the lady's paternal aunt. X is also the sister of F1 and therefore the man's paternal aunt. This matches the statement exactly and places the man and the lady in the same generation as cousins.

Why Other Options Are Wrong:
Daughter of the man: This would place the lady one generation below the man, which contradicts the shared aunt configuration.Niece of the man: If the lady were his niece, her parent would be the man's sibling, which does not fit the description of the common aunt.Sister of the man: If they were siblings, they would share both parents and would not need the more complex aunt relationship described.Aunt of the man: This would place the lady one generation above him, which again conflicts with the given structure.

Common Pitfalls:
A frequent mistake is to treat the phrase your mother's husband's sister as the man's mother, which is incorrect. Another common error is to ignore that the same woman must fit simultaneously as the lady's paternal aunt and the man's aunt. Once that double role is recognized, the cousin relationship between the man and the lady becomes clear.

Final Answer:
The lady is the cousin of the man.