1. Which of the following describes a concern when using fax machines? A. Their encryption can be broken easily. B. The fax might be directed to the wrong place. C. They're too expensive. D. They take too long.

How is the central idea developed further? (a) the author elaborates on the treatments for allergies in adults and how they work. (b) the author quotes the reactions of experts and the methods used to conduct the study. (c) the author compares the different rates of food allergies shown in children and adults. (d) the author indicates the limitations of the study because of differences in health care.