Can you tell me _______to talk to and ________to get help when we have problems?

A．who; where

B．who; what

C．what; who

D．where; when

云南某市举办园艺博览会，荷兰一公司有一批郁金香种苗参展，在取得《中华人民共和国动植物检疫许可证》证后方可进境。