The correct answer is A. I was kept awake by the noise of the traffic.
The other options are incorrect because they do not accurately reflect the meaning of the sentence.
Option B, The traffic kept me awake by noise, is incorrect because it implies that the traffic was the only factor that kept the speaker awake. It is possible that other factors, such as a lack of sleep or an illness, also contributed to the speaker’s sleeplessness.
Option C, I kept myself awake due to the noise of the traffic, is incorrect because it implies that the speaker was responsible for their own sleeplessness. It is possible that the speaker tried to sleep but was unable to due to the noise of the traffic.
Option D, I remained awake by the noise of the traffic, is incorrect because it implies that the speaker was able to stay awake despite the noise of the traffic. It is possible that the speaker was only able to stay awake for a short period of time before falling asleep.