Step-by-step Solution:

Quick Solution

To solve this, we will build the family tree by connecting the individuals based on the clues. Then, we will use the given counts of adults/children and males/females to determine the final relationships and answer the question.

1. Building the Family Structure

• From "A and D are brothers," we know A and D are Male.
• From "B is married to D," we know B is Female (as she is married to the male D).
• From "E is an engineer married to one of the brothers," since D is already married to B, E must be married to the other brother, A. This means E is the wife of A, and therefore E is Female.
• The family has 4 adults and 3 children. The adults must be the two married couples: (D, B) and (A, E).
• The three children are F, G, and C.
• From "G is their child" (referring to B and D), we know G is the child of B and D.
• From "E has two children," the other two children, F and C, must be the children of A and E.

2. Determining Genders with the Final Count

The family has a total of 3 males and 4 females. Let's tally the genders we have identified so far from the relationships and clues:

• Known Males (2): A, D
• Known Females (3): B, E, and G (clue says F and G are girls).
• This leaves F and C. We know from the clues that F is a girl (Female).
• Our count is now 2 Males and 4 Females. To match the required total of 3 Males and 4 Females, the last remaining person with an unknown gender, C, must be Male.

3. Conclusion: Who is C?

Based on our step-by-step deduction, we have established the following facts about C:

• C is a Male.
• C is the child of A.

Therefore, C is A's son.

Final Answer: C is A's son.