全球经济下行压力之下。中小企业发展愈加困难。为此，我国进一步加大结构性减税力度，拓宽减税范围。为中小企业减负，促进其转型发展。这有利于

A．贯彻按劳分配原则

B．增强中小企业的营利能力

C．解决消费不足问题

D．发挥中小企业的主导作用

The scientists have made an exhaustive study of the virus _______ many people have been inflected.

A．to which

B．in which

C．with which

D．for which