Final answer:
The percentage of chronically ill patients in the population is 10%, but the exact percentage of health care costs accounted for by these patients is not specified in the given information.
Step-by-step explanation:
According to the information provided, the percentage of chronically ill patients in the population is 10%.
However, the exact percentage of health care costs accounted for by chronically ill patients is not specified or directly mentioned in the given information. Therefore, we cannot determine the correct answer from the options provided.