According to the information in Paragraph 2, which of the following statement is true of d

According to the information in Paragraph 2, which of the following statement is true of drugs？

A．All drugs are of no use at all in treating the influenza symptoms

B．Most drugs can greatly relieve the influenza symptoms at any time.

C．Prescribed drugs are relatively effective only under certain conditions

D．Drugs are more useful and effective than vaccines in curing influenza.

请帮忙给出正确答案和分析，谢谢！