下列预防传染病的措施中，属于切断传播途径的是（　　）

A．接种乙肝疫苗

B．将疫区病禽扑杀、焚烧和深埋处理

C．打扫卫生，消灭蚊、蝇等

D．加强体育锻炼，增强抵抗能力

— Do you know _____?

— I'm not sure. Maybe he is a businessman.

[      ]

A. who he is

B. what he does

C. where he lives