The discrepancy presented in the information is that preschool children who spend their days in daycare nurseries are ill more often than those who do not, but when they reach school age, they tend to be ill less often than their classmates who did not attend daycare nurseries during their preschool years.
To explain this discrepancy, we need to find a statement that provides a reasonable explanation for why these children are less prone to illness when they reach school age despite being more frequently ill during preschool.
Among the answer choices:
(A) There are many common infectious illnesses that circulate quickly through a population of school-age children, once one child is infected.
- This statement discusses the rapid spread of infections in school-age children but doesn't directly address why the children who attended daycare nurseries during preschool become less prone to illness at school age.
(B) Those children who have older siblings are likely to catch any common infectious illnesses that their older siblings have.
- This statement is about the transmission of illnesses from older siblings but doesn't explain why children who attended daycare nurseries during preschool become less prone to illness at school age.
(C) By school age, children who have been in daycare nurseries have developed the immunities to common childhood illnesses that children who have not been in such nurseries have yet to develop.
- This statement directly addresses the discrepancy by suggesting that the children who attended daycare nurseries during preschool have developed immunities to common illnesses, making them less prone to illness at school age.
(D) The number of infectious illnesses that children in a daycare nursery or school develop is roughly proportional to the number of children in the facility, and daycare nurseries are smaller than most schools.
- This statement discusses the size of daycare nurseries and schools but does not directly explain why the children who attended daycare nurseries during preschool are less prone to illness at school age.
(E) Although in general the illnesses that children contract through contact with other children at daycare nurseries are not serious, some of those illnesses if untreated have serious complications.
- This statement discusses the seriousness of illnesses contracted at daycare nurseries but does not directly explain why these children are less prone to illness at school age.
Option (C) is the most suitable choice because it provides a logical explanation for the observed discrepancy. Children who attend daycare nurseries during preschool are exposed to common childhood illnesses, which helps them develop immunity, making them less prone to these illnesses when they reach school age. This aligns with the information presented in the passage.