To prevent the spread of any disease, it is necessary to

Solution

Let's have a look at all the statements given:

A) Medicines have been developed against a wide range of bacteria. → If this is true strengthens the given argument as the passage is talking about the importance of taking medicines.

B) Antibiotics do not work against viruses. → The passage is talking about bacteria and not viruses. Also, it is referring to medicines in general and not antibiotics in particular. Hence, this if true, doesn't have any impact on the argument given.

C) Overdosing of medicines can lead to bacteria getting resistant to that medicine. → This statement, if true, weakens the argument as the passage is talking about taking medicines even after no symptoms. But this statement is throwing light on the drawback of taking medicines more than needed. Overdosing can nullify the effect of the medicine on the bacteria against which it has to be taken.

D) Bacteria are the only disease-causing agents. → This statement, if true, strengthens the argument as the passage is based on bacteria only.

E) Doctors are always right in prescribing the dosage and duration of medicine. → This statement also strengthens the argument, if true, as the passage is also suggesting to take the medicines till the prescribed duration and as per the prescribed dosage despite no symptoms in order to recover fully.

Hence, the correct answer is Only C.