The correct answer is C. I was kept awake by the noise of the traffic.
The sentence “The noise of the traffic kept me awake” is in the passive voice. In the passive voice, the subject of the sentence is acted upon by the verb. In this case, the subject is “I” and the verb is “kept awake.” The passive voice is often used when the focus of the sentence is on the action, rather than the person or thing doing the action. In this case, the focus is on the fact that the noise of the traffic kept me awake, not on who or what caused the noise.
The other options are incorrect because they are in the active voice. In the active voice, the subject of the sentence is doing the action. In these cases, the subjects are “I” (A), “the noise of the traffic” (B), and “the traffic” (D). The active voice is often used when the focus of the sentence is on the person or thing doing the action. In these cases, the focus is on the fact that I remained awake (A), the noise of the traffic kept waking me (B), or the traffic kept me awake (D). However, the focus of the original sentence is on the fact that the noise of the traffic kept me awake, not on who or what caused the noise.