In the following sentences, the incorrect part of the sentence is underlined. Choose an alternative from the four given options so that the sentence is rendered correct.

If I had known that you needed to go to the airport yesterday, I could drive you there.

Option 3: would have driven you there is correct.

When a sentence begins with "If I had known..." (called the third conditional), we are talking about an imaginary situation in the past — something that didn't actually happen. The correct structure is:

If + past perfect, ... would have + past participle.

Here, the speaker is saying: "I didn't know you needed a ride, but if I had known, I would have driven you."

Now let's confirm by eliminating the other options:

Option 1 → "Should have driven" has the correct past form, but "should" implies obligation (like "I was supposed to"). The sentence is about willingness, not duty.

Option 2 → "Should drive" is present tense, but the event happened yesterday. Plus, "should" again implies obligation. Doesn't work.

Option 4 → "Would drive" has the right idea (willingness), but misses the past form. Since the situation is entirely in the past, we need "would have driven," not just "would drive."

Hence, Option 3 is correct.