Explanation:

- Option 1: "you when you was"

- This part contains an error. The correct usage should be "you when you were" instead of "you when you was." The subject "you" should be paired with the verb "were."

- Option 2: "No error"

- This option implies that there are no mistakes in the sentence, but that's incorrect since there's a verb agreement error.

- Option 3: "a small boy"

- This is a correct phrase. It accurately describes "a small boy" without any grammatical issues.

- Option 4: "I liked talking to"

- This phrase is also correct. It introduces the sentence properly and doesn't contain any errors.

Answer: Option 1: "you when you was"