Select the most appropriate option to substitute The monitor of the class don’t know the answer.

Explanation:

The subject is "The monitor", not "the class."

Here, monitor is singular, so we use:

✔️ doesn't know
❌ don't know

Correct sentence:

The monitor of the class doesn’t know the answer.

Rule Used: Subject–Verb Agreement

The verb must agree with the main subject, not with words that come after of.

Structure:
Main Subject + of + noun

Examples:

• The leader of the team is absent. ✔️
• The students of the class are present. ✔️
• The monitor of the class doesn't know the answer. ✔️

Why other options are incorrect?

❌ doesn’t knew → after doesn't, use the base form (know), not knew
❌ didn’t knew → after didn't, use know, not knew
❌ don’t knew → both verb forms are wrong

Extra Facts:

📘 After do / does / did, always use V1 (base form):

• Does she play? ✔️
• Did he go? ✔️
• Doesn't he know? ✔️