GWD10.谢谢~

40.Until now,only injectable vaccines against influenza have been available.Parents are reluctant to subject children to the pain of jijections,but adults,who are at risk of serious complications from influenza,are commonly vaccinated.A new influenza vaccine,administered painlessly in a nasal spray,is effective for children.However,since children seldom develop serious complications from influenza,no significant public health benefit would result from widespread vaccination of children using the nasal spray.

Which of the following is an assumption on which the argument depens?

D.Adults do not contract influenza primarily from children who have influenza.

E.The nasal spray vaccine is not dffective when administered to adults.

为什么是D类?