Critical Reasoning (CR) | Re: It is widely assumed that people need to engage in intellectual activi

Dear Experts,

I have really read all the comments and explanation in this thread.
But I am still confused (B).
I understand why (E) and others are wrong. but I am not convinced why (B) is correct.

The passage doesn't mention anything about medical conditions. I understand that weaken and strengthen can be out of scope but (B) doesn't tell anything about relation between Mental Sharpness and Social Contact.

Even third factor, such as medical conditions, does affect or cause both Mental Sharpness
...

---