At a wedding reception, a man pointed towards the groom and said, "The groom is the brother of the son of the son of my grandfather."

What is the groom's relation to that man?

The correct option is Brother.

Step-by-Step Explanation:

We can solve this blood relation puzzle by breaking down the man's statement step-by-step from the innermost relation outwards:

1. "My grandfather" refers to the man's grandfather.
2. "The son of my grandfather" refers to the man's father.
3. "The son of the son of my grandfather" refers to the son of the man's father, which represents either the man himself or his brother.
4. "The groom is the brother of..." that person. Therefore, the groom is the man's brother.

Hence, the groom is related to the man as his Brother.