The original paragraph is: "Another familiar disease is malaria, which Elizabethans refer to as ague or fever. You might associate this with more tropical countries of the modern world but in marshy areas in sixteenth-century England, such as the Lincolnshire and Cambridgeshire Fens, the Norfolk Broads, and Romney Marsh in Kent, it kills thousands. No one suspects that it has anything to do with mosquitoes; rather people believe it is the corrupted air arising from the ling dank marsh (hence the term mal-aria). As a result, you will have no chance of getting proper treatment for the disease."
The correct answer is "it explains the Elizabethan misconceptions about the spread of malaria."
This is because people of Elizabethan England did not suspect mosquitoes from the Marsh (since mosquitoes thrive in wet or damp environments) are the main animal vectors for malaria. Also, since the etiologic agent of malaria is not yet identified at that time, the treatment is almost impossible to give.