1. 
Fact 1: Jessica has four children
Fact 2: Two of the children have blue eyes and two of the children have brown eyes.
Fact 3: Half of the children are girls.
If the first three statements are facts, which of the following statements must also be a fact?
I: At least one girl has blue eyes.
II: Two of the children are boys.
III: The boys have brown eyes.

A. I only
B. II only
C. II and III only
D. None of the statements is a known fact.

Answer: Option B

Explanation:

Since one-half of the four children are girls, two must be boys. It is not clear which children have blue or brown eyes.