When the passive voice is changed to active voice, the object and the subject of the sentence interchange their positions, the focus is the subject performing the action. The verb of the sentence changes into its active form. However, the tense of the sentence is not changed.

Option B is correct as it correctly converts the passive to active while keeping the future perfect tense of the sentence intact.

Options C and D are incorrect as they are not in the future perfect tense. In option A, the interrogative sentence has also been changed into a declarative sentence and it is in passive voice so it is not acceptable.