Despite improvements in treatment for asthma, the death rate from this disease
has doubled during the past decade from its previous rate. Two possible
explanations for this increase have been offered. First, the recording of deaths due
to asthma has become more widespread and accurate in the past decade than it
had been previously. Second, there has been an increase in urban pollution.
However, since the rate of deaths due to asthma has increased dramatically even in
cities with long-standing, comprehensive medical records and with little or no urban
pollution, one must instead conclude that the cause of increased deaths is the use
of bronchial inhalers by asthma sufferers to relieve their symptoms.

Which one of the following is an assumption on which the argument depends?

(A) Urban pollution has not doubled in the past decade.

(B) Doctors and patients generally ignore the role of allergies in asthma.

(C) Bronchial inhalers are unsafe, even when used according to the recommended
instructions.

(D) The use of bronchial inhalers aggravates other diseases that frequently occur
among asthma sufferers and that often lead to fatal outcomes even when the
asthma itself does not.

(E) Increased urban pollution, improved recording of asthma deaths, and the use of
bronchial inhalers are the only possible explanations of the increased death rate
due to asthma.

OA after a few replies.