Chọn từ thích hợp trong ngoặc: He is the man (who / whom / which) was helped last night

7-He is the man (who/whom/which) was helped last night.
8-Hoa’s parents,(who/whom/which ) work very hard to earn their living, are farmers.
9-My Tam, (who/whom/that) you saw on tv ,is a beautiful singer.