Until now, only injectable vaccines against influenza have been available. Parents are reluctant to subject children to the pain of injections, 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 depends?A. Any person who has received the injectable vaccine can safely receive the nasal-spray vaccine as Well B. The new vaccine uses the same mechanism to ward off influenza as jnjectable vaccines do. C. The injectable vaccine is affordable for all adults. D. Adults do not contract influenza primarily from children who have influenza. E. The nasal spray vaccine is not effective when administered to adults.

The conclusion from this argument is that there is no health benefit for the nasal spray vaccine since it was designed to be administered to children, but children rarely get influenza.

The only assumption that strengthens this conclusion is that children do not pass influenza to adults.

If this is true, plus the fact that children rarely get influenza, then why would anyone need an influenza vaccine for children.
If this assumption was false and children passed influenza to adults, then the conclusion would be wrong because a vaccine would be necessary to prevent children from passing influenza.