Which of the following is a key characteristic of the 'already but not yet' eschatology found within the New Testament?

A The complete fulfillment of all prophetic promises at the moment of Jesus' resurrection. B The tension between the present reality of God's kingdom and its future consummation. C The belief that the kingdom of God is solely a future reality with no present manifestation. D The idea that believers must achieve perfect righteousness before experiencing any benefits of salvation.