The correct option is C Future Perfect Continuous Tense
The tense of a sentence denotes a time, whether it is the time now (present), time then (past) or the time to come (future). The verb of a sentence has most to do with the tense. The given sentence is of the form will have been + present participle (living), the same as that of the future perfect continuous tense, that describes an action that will continue even after a certain point of time, hence option D is correct. The form used in the future continuous tense is shall/will be + present participle, in the past perfect continuous tense the form is had been + present participle and the form used in the present perfect continuous tense is has/have been + present participle. The given sentence contains none of these forms, hence options A B, C are incorrect.