Certain Researchers Have Published Peer-Reviewed Reports That the Use of Zinc

Multiple Choice

Certain researchers have published peer-reviewed reports that the use of zinc lozenges reduces the length and severity of cold symptoms. What is one reason why some scientists are still skeptical about the merits of using zinc lozenges during a cold?

A) Because most people get zinc in their diet anyway, there's no reason to believe that zinc lozenges could affect a cold.
B) Previous ideas about vitamin C usage have been discredited, so there's no reason to believe new ideas about zinc lozenges.
C) There is no way of knowing if the original work was properly controlled or statistically significant.
D) There may be other reasons why the people taking zinc lozenges recovered faster, such as stress levels or differences in their immune systems.