The correct option is D Yet
The sentence needs to add a sense of time to the action given by its verb. So, it needs an adverb of time. An adverb of time is a word that describes when, for how long, or how often a certain action happened. Option D is the correct answer as ‘yet,’ as an adverb of time adds the sense of time to the statement. Options A, B and C cannot be used here as they will render the statement meaningless.