【正确答案】 C

【答案解析】解析：convenience n.方便，便利；方便条件，便利条件(如：He thinks only of his own convenience．Will the time／place suit your convenience?at sb．’s convenience在某人方便的时候；to sb．’s convenience对某人合适)。facility n.便利，容易；(pl.)设备，设施。duty n.职责；责任，义务。comfort n.舒适；安慰。