请教: GWD18-15

GWD-18-Q15
Fact: Asthma, a bronchial condition, is much less common ailment than hay fever, an allergic inflammation of the nasal passages.
Fact: Over 95 percent of people who have asthma also suffer from hay fever.

If the information given as facts above is true, which of the following must also be true?

A. Hay fever is a prerequisite for the development of asthma.
B. Asthma is a prerequisite for the development of hay fever.
C. Those who have neither hay fever nor asthma comprise less than 5 percent of the total population.
D. The number of people who have both of these ailments is greater than the number of people who have only one of them.
E. The percentage of people suffering from hay fever who also have asthma is lower than 95 percent
   Answer: E

不明白, 哪位NN帮忙解释一下.

a math problem.

fact 1: asthma < hey fever

fact 2: 95% of asthma has hey fever

画两个圆, 一个大表示hey fever, 一个小表示asthma. 重叠一下, 马上就看出来了.