The correct option is B Yet
The sentence talks about an action that has not been accomplished but will be done in near future. 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. Here, ‘Yet,’ as an adverb of time can bring out the meaning of the action unfinished now and to be accomplished. Hence, Option D is the correct answer. Options A, B and C cannot be used as they would render the sentence meaningless.