There was a man ________ had four sons. He wanted his sons to learn not to judge things too quickly.

Correct option is C

 • The blank refers to a person (a man).

• “Who” is used as a relative pronoun for people.

• Correct sentence:
There was a man who had four sons.

Meanings of other options:
• those – plural demonstrative
• that – used for both but less preferred for people
• whom – used as object, not subject

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