Critical Reasoning

In malaria-infested areas, many children tend to suffer several bouts of malaria before becoming immune to the disease. Clearly, what must be happening is that those children’s immune systems are only weakly stimulated by any single exposure to the malaria parasite and need to be challenged several times to produce an effective immune response.
Which of the following, if true, most seriously undermines the explanatory hypothesis?
(A) Immediately after a child has suffered a bout of malaria, the child’s caregivers tend to go to great lengths in taking precautions to prevent another infection, but this level of attention is not sustained.
(B) Malaria is spread from person to person by mosquitoes, and mosquitoes have become increasingly resistant to the pesticides used to control them.
(C) A certain gene, if inherited by children from only one of their parents, can render those children largely immune to infection with malaria.
(D) Antimalaria vaccines, of which several are in development, are all designed to work by stimulating the body’s immune system.
(E) There are several distinct strains of malaria, and the body’s immune response to any one of them does not protect it against the others

I think its E as all others are out of scope in the context of the given information.

Whats the OA?

https://www.theecogeek.wordpress.com

OA is E.
Can you explain please

(A) Immediately after a child has suffered a bout of malaria, the child’s caregivers tend to go to great lengths in taking precautions to prevent another infection, but this level of attention is not sustained.
this talks about attention required after malaria, doesn't help in undermining the given explanation.

(B) Malaria is spread from person to person by mosquitoes, and mosquitoes have become increasingly resistant to the pesticides used to control them.
the argument talks of immunity towards the parasights and has nothing to do with mosquitoes

(C) A certain gene, if inherited by children from only one of their parents, can render those children largely immune to infection with malaria.
this doesn't explain why immune system doesn't work in case of malaria

(D) Antimalaria vaccines, of which several are in development, are all designed to work by stimulating the body’s immune system.
The explanation talks nothing about the substances outside the human body so this is out of the scope

(E) There are several distinct strains of malaria, and the body’s immune response to any one of them does not protect it against the others
This is perfect as it tells that not all types of malaria are opposed by the immune system of the body

But how does choice E account for the fact that "children suffer several bouts of malaria before becoming immune to the disease"? If there are several strains of malaria, and the body's immune response to any one of them does not protect it against the others, then shouldn't the children be continuously infected by malaria?

Please explain.

Hi,

The conclusion in the argument is " [b]children’s immune systems are only weakly stimulated by any single exposure to the malaria parasite and need to be challenged several times to produce an effective immune response[/b]" meaning for a child to be completely immune to malaria then he must be infected multiple times and the Option E provides a explanation that weakens this conclusion by stating that the multiple occurences of malaria in a child is because the medication taken for one trace will not prevent the other trace of malarial parasite attacking the child

(D) in a way is strengthening the argument. It shows that multiple exposures to malarial bouts are indeed responsible for strengthening the immune response of children. The additional info that the choice here provides is the Antimalarial vaccines are now acting as the middle agent for strengthening the immune response necessitating the use of multiple exposures. So (D) instead of weakening, strengthens the argument.

Thanks
Prashant