I () call Mike last night, but I got busy and didn't do it.

• A. Meant to
• B. Might have
• C. Would have
• D. Should have

Answer: (A)

The idea being tested is expressing a past intention that didn’t happen. “Meant to” fits because it conveys what you planned to do in the past: I meant to call Mike last night, but I got busy and didn’t do it. The phrase “meant to” is followed by the base form of the verb, so “call” stays in its plain form after it.

The other options don’t fit this exact sense. They express possibility or obligation or a conditional idea, and they would require a different verb form (like “called” after them) or change the nuance of the sentence entirely.