Select the odd word (odd type of family relationship) from the given alternatives.

Introduction / Context:

This verbal reasoning question asks you to select the odd word from a list of four family-relationship terms. Although all the options look similar at first glance, only one of them belongs to a different conceptual category. Such questions test your understanding of basic blood relations and the difference between relations by blood and relations by marriage, which is very important for blood-relation reasoning problems in competitive exams.

Given Data / Assumptions:

• The options are: Mother-in-law, Nephew, Grandson and Great grandfather.
• We assume standard family terminology used in Indian and international reasoning questions.
• Blood relations are those formed by birth, such as parent, child, grandparent, grandson and nephew.
• Relations by marriage are those formed only after a marriage tie, such as mother-in-law, father-in-law, brother-in-law and sister-in-law.
• We need to pick the term whose type of relationship is different from the others.

Concept / Approach:

The key idea is to classify each relation as either a blood relation (consanguineous) or an in-law relation (affinal). Nephew, grandson and great grandfather all represent direct or indirect blood ties across generations. Mother-in-law, however, is defined purely through marriage: she is the mother of one's spouse. Once we sort the options according to this concept, the odd one out becomes clear.

Step-by-Step Solution:

Verification / Alternative check:

Another way to verify is to ask: "If there were no marriages at all, which relations could still exist?" Nephews, grandsons and great grandfathers can exist in a family tree formed purely through births. However, a mother-in-law can exist only when someone marries: you must have a spouse whose mother becomes your mother-in-law. This confirms that mother-in-law is structurally different from the rest.

Why Other Options Are Wrong:

"Nephew" is a close blood relation through siblings and is not formed only by marriage, so it belongs in the blood-relations group.

"Grandson" is also a direct blood descendant, so it fits with the other blood relations.

"Great grandfather" is a direct blood ancestor several generations above and is therefore similar in nature to grandson and nephew.

Common Pitfalls:

Some learners focus only on the age or generational distance, thinking that "great grandfather" is odd because it feels more distant. However, the question is not about age but about type of relation. All of the terms except mother-in-law can be placed purely on a blood-based family tree. Always check whether a relation requires a marriage link (in-law) or arises solely from birth when solving these kinds of "odd one out" problems.

Final Answer:

The odd word is Mother-in-law, because it represents a relation by marriage, whereas the others are blood relations.