Complete the sentence using the most appropriate option:A friend of yours offers you a lift in his car but you decide to walk.You say: Thank you but _________________. A. I think I have walked. B. I think I’d walk. C. I think I’ll walk. D. I think I am walking.

The correct answer is: C. I think I’ll walk.

The other options are incorrect because they do not make sense in the context of the sentence.

• Option A, “I think I have walked,” is incorrect because it implies that you have already walked, which is not the case.
• Option B, “I think I’d walk,” is incorrect because it implies that you are considering walking, but you have already decided to walk.
• Option D, “I think I am walking,” is incorrect because it implies that you are currently walking, which is not the case.

The correct answer, “I think I’ll walk,” is the most appropriate option because it expresses your decision to walk in a polite and concise way.