This problem comes with two conflicting statements.
Each of John's friends claims to know someone who has smoked 40 cigarettes a day for the last 40 years who is healthy
John doesn't know any such smokers. John is quite certain he is not the only one in his friend group who doesn't know a smoker like this.
The question stem tells us we must assume that all statements in the passage are true. John's position is presented as fact, which is why we know that at least one of his friends is mistaken or lying. This is why answer choice E is correct.
Answer choice B is incorrect, because the passage does not tell us anything about people's motives. We have no idea why some of his friends aren't telling the truth, and the passage does not prove that exaggeration is the cause.
