My brother said, "Somebody needs to alert the people on the boat. But don't forget about the people in the tower!" I replied, "I'll alert them." In the above exchange, A) "them" refers to the people on the boat only. B) "them" refers to the people in the tower only. C) it is unclear what the antecedent is for "them." D) "them" refers to both the people on the boat and the people in the tower.