GMAT Critical Reasoning (CR) | Re: A large amount of rainfall in April and May typically leads to

A large amount of rainfall in April and May typically leads to an increase in the mosquito population and thus to an increased threat of encephalitis. People cannot change the weather. Thus people cannot decrease the threat of encephalitis.

The reasoning in the argument above is flawed in that the argument:

(A) takes for granted that becauseone event precedes another the former must be the cause of the latter
(B) presumes, without providing justification,that a certain outcome would be desirable