All people they are old or young rich or poor have been trying their best to help those

问题补充：

All people,they are old or young, rich or poor, have been trying their best to help those in need since the disaster.

A. even if

B. whether

C. no matter

D. however

答案：

A. even if

(答案→)B. whether

C. no matter

D. however

解析：本题考查固定词组搭配。whether…or…表示“无论……还是……”