Analyze Key Relationship Clues

Break down the core statements provided in the question:

• The man in the picture is the grandmother's only son.
• This man is not the brother of the speaker's mother.
• The speaker's mother has exactly two children: a daughter and a son.

Identify the Man's Role

Let's analyze the critical statement: "he was the only son of our grandmother, but he was not the brother of our mother."

• The "grandmother" is the mother of both the man and the speaker's "mother". This makes the man and the mother siblings.
• The statement "he was not the brother of our mother" creates a logical puzzle. If they are siblings, he should be her brother.
• The most logical resolution is that the man is the Father of the speaker. Let's verify this:
  • If the man is the Father, he is the son of the speaker's Grandmother. This aligns with "only son of our grandmother".
  • If the man is the Father, he is the husband of the speaker's Mother, hence not her brother. This satisfies "not the brother of our mother".
• This interpretation resolves the apparent contradiction.

Determine Speaker's Relationship

We know the speaker's mother had two children: a daughter and a son.

• From the previous step, the man in the picture is identified as the speaker's Father.
• The question asks how "I" (the speaker) am related to this man (the Father).
• The speaker is either the daughter or the son mentioned in the mother's children.
• Given the correct option is "Son", it implies the speaker is the son mentioned.
• Therefore, the speaker ("I") am the Son of the man (who is the Father).