U is nephew of D who is sibling of B. R has two children. B is only son of M who is spouse of R. K is mother of U. Gender of K and M is same. How R is related to U?

To find the relationship between R and U, let us break down the family clues step-by-step:

Step 1: Determine the children of R and M
- "B is the only son of M who is the spouse of R." This tells us that M and R are a married couple, and B is their son.
- "R has two children," and "D is the sibling of B." This means the two children of R and M are B and D.
- Since B is the only son, the other child, D, must be a daughter (female).

Step 2: Find the parents of U
- "U is the nephew of D." Since D's only sibling is B, U must be the son of B.
- "K is the mother of U." Since U is B's son and K is U's mother, B (male) and K (female) are married. Thus, K is female.

Step 3: Determine the genders of M and R
- "The gender of K and M is the same." Since K is female, M is also female.
- Since M is female and is married to R, R must be male.

Step 4: Connect R to U
- R (male) is the father of B.
- B is the father of U.
- Therefore, R is the grandfather of U.