GMAT Critical Reasoning (CR) | Re: A researcher discovered that people who have low levels of

I guess that this question got me (and probably other non-native speakers as well) because I misunderstood how "as well as" is being used.

Conclusion is: "The researcher concluded that the immune system protects against mental illnessas well as against physical disease".
If you understand is as: the immune system protects against mental illnessand
the immune system protects against against physical disease
then indeed answer B is tempting.

But
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