Let me do this.

The correct answer is: C. Let this be done by me.

The other options are incorrect because they do not convey the same meaning as the original sentence.

• Option A, “Let us do this,” suggests that the speaker is asking for permission to do something with another person or group of people.
• Option B, “This is to be done by me,” is a passive sentence that does not indicate who is doing the action.
• Option D, “Let I do this,” is grammatically incorrect. The correct way to say this would be “Let me do this.”

The original sentence, “Let me do this,” is a direct request from the speaker to be allowed to do something. The speaker is confident in their ability to do the task and is asking for permission to take on the responsibility.