'You will boost your immune system if you exercise...

Câu hỏi: 'You will boost your immune system if you exercise regularly,' said Tam.

A. Tam says that we'll boost our immune system if we exercised regularly.

B. Tam said that we'd boost our immune system if we exercised regularly.

C. Tam said that we'll boost our immune system if we exercised regularly.

D. Tam said that we boost our immune system if we exercised regularly.