select the most appropriate word to fill in the blank. If I ________ that you were coming over, I would have cancelled my programme. (a) Know (b) Knows (c) had known (d) am knowing

Options

A. Know
B. Knows
C. had known
D. am knowing

Explanation

“had known” should be used.
RULE: The verb in the If clause is in the past perfect tense, the verb in the Main clause is perfect conditional.
Sentence Structure: If + Past Perfect, Subject would + have + Verb (`3^("rd")` form) In this sentence, the main clause is perfect conditional (would + have + verb III) so the if clause should be in the Past Perfect Tense.