The question is testing knowledge of verb tenses. The 'Present Perfect Continuous' tense is used to describe an action that started in the past and is still happening now. 'Past Perfect' is used for an action that was completed before another past action. 'Future Perfect' is for an action that will be completed before a future time. 'Past Continuous' is for an action that was happening at a specific time in the past. Therefore, the correct answer is B. Present Perfect Continuous.