Recently, a court ruled that current law

Recently, a court ruled that current law allows tour operators that travel to potentially dangerous locations, such as the Amazon, to reject a potential customer if there is a 50 percent chance that the traveler would contract malaria on the trip. The presiding judge justified the ruling, saying that it protected both travelers and tour operators.

This use of his court ruling as part of the law could not be effective if which of the following were true?

(A) The best interests of travelers often conflict with the interests of tour operators.

(B) There is currently no legally accepted method existing for calculating the risk of contracting malaria as a result of being exposed to it in a particular location.

(C) Some trips might involve health risks other than the risk of malaria.

(D) Travelers who have a 50 percent chance of contracting malaria may be unaware that their risk is so great.

(E) The number of people signing up to take trips with a tour company might decline if the company, by screening applicants for risk of malaria, seemed to suggest that the trip entailed high risk of getting the disease.

The best answer is B.  The use of the court ruling as part of the law could not be effective if there were no accepted way of determining who the people susceptible to malaria were.  Choice b states that there is no accepted method of calculating the risk of contracting malaria.