International students are almost always invited, through organized ______ activities, into the homes of Americans living in or outside the academic community.
 
【正确答案】 A
【答案解析】 选项中的词均以-lity结尾。hospitality“热情招待，殷勤好客”；hostility来自形容词hostile(不友善的，敌对的)，“敌意，对抗”；disability“残疾；无能；无资格”；possibility“可能性；可能发生的事物”。根据句中谓语invited判断，hospitality符合句意，故答案为A。