Let's break down the given relationships step by step to determine how 'D' is related to 'B'.

Understanding the Given Blood Relations

We are provided with several pieces of information connecting different individuals:

• 'D' is the son of 'F'. This tells us the gender of D (male) and establishes a parent-child link. We can write this as: \( F \rightarrow D \) (D is son).
• 'E' is the sister of 'F'. This means E and F are siblings. We can write this as: \( E \leftrightarrow F \) (E is sister of F). This implies F is the sibling of E (either brother or sister).
• 'E's son is 'A'. This tells us the gender of A (male) and a parent-child link from E. We can write this as: \( E \rightarrow A \) (A is son).
• 'E's daughter is 'X'. This tells us the gender of X (female) and another parent-child link from E. We can write this as: \( E \rightarrow X \) (X is daughter).
• 'B' is the maternal uncle of 'A'. A's mother is E. A's maternal uncle is the brother of A's mother (E). Therefore, B is the brother of E. This tells us the gender of B (male) and establishes a sibling link with E. We can write this as: \( B \leftrightarrow E \) (B is brother of E).

Connecting the Family Members

From the relationships, we can establish the connections among B, E, and F, and then extend to D and A/X:

1. We know 'B' is the brother of 'E'.
2. We know 'E' is the sister of 'F'.

Combining these two points, B, E, and F are siblings. Since B is E's brother and E is F's sister, B must also be a sibling of F. B is male.

So, B, E, and F are siblings. B is a brother. E is a sister. F can be either a brother or a sister based on the information so far.

Now consider the next generation:

• 'D' is the son of 'F'. So D is in the generation below F.
• 'A' and 'X' are the children of 'E'. So A and X are in the generation below E.

Determining the Relationship between D and B

We need to find the relationship between 'D' and 'B'.

We know:

• 'D' is the son of 'F'.
• 'F' is a sibling of 'B' (either brother or sister).

If F is B's brother or sister, then F's child is B's nephew (if male) or niece (if female).

The problem states that 'D' is the son of 'F', meaning D is male.

Therefore, 'D', being the son of B's sibling 'F', is B's nephew.

Family Structure Overview

We can represent the family relationships like this:

Since D is the son of F, and F is a sibling of B, D is the nephew of B.

Checking the Options

Let's look at the given options:

• A. Cousin: A cousin is the child of one's aunt or uncle. D is the child of B's sibling, so this is incorrect.
• B. Nephew: A nephew is the son of one's brother or sister. D is the son of F, and F is B's sibling. D is male. This fits the definition of a nephew.
• C. Maternal Uncle: A maternal uncle is the brother of one's mother. B is D's parent's sibling. D's parent is F. B is F's sibling, not D's maternal uncle.
• D. Brother: A brother is a male sibling of the same generation. D is in the generation below B. This is incorrect.

Based on the analysis, 'D' is the nephew of 'B'.

Conclusion

By carefully tracing the relationships provided, we determined that B, E, and F are siblings, with B being male. D is the son of F. Therefore, D is the son of B's sibling, making D the nephew of B.

Revision Table: Key Relationships

Combining E <-> F and B <-> E means B, E, F are siblings. Since D is son of F, D is nephew of B.

Additional Information on Blood Relations

Solving blood relation questions requires careful construction of a family tree or diagram based on the given information. Key terms and their meanings are crucial:

• Parent: Mother or father.
• Child: Son or daughter.
• Sibling: Brother or sister.
• Uncle: Brother of one's parent.
• Aunt: Sister of one's parent.
• Maternal Uncle/Aunt: Brother/Sister of one's mother.
• Paternal Uncle/Aunt: Brother/Sister of one's father.
• Nephew: Son of one's brother or sister.
• Niece: Daughter of one's brother or sister.
• Cousin: Child of one's uncle or aunt.
• Grandparent: Parent of one's parent.
• Grandchild: Child of one's child.

Always identify the gender of individuals when specified (e.g., son, daughter, brother, sister, uncle, aunt). Use symbols or diagrams to keep track of relationships across generations and between individuals.