Psychiatrist: Research shows that teenagers who use tobacco

Psychiatrist: Research shows that teenagers who use tobacco products on a regular basis are three times as likely to develop mental abnormalities as are teenagers who do not use any tobacco products.

Federal legislation that prohibits the sale of tobacco products to minors would help curb this health problem among teenagers.

The psychiatrist’s conclusion depends on which of the following assumptions?

A) The majority of federal legislators would vote for a bill that prohibits the sale of tobacco products to teenagers.
The conclusion talks about the effectiveness of the legislation, the fact supported by A does not affect it. We need to find an answer that goes against hypothetical effectiveness of the law.

B) Not all teenagers who consume tobacco products on a regular basis suffer from mental abnormalities.
Same as A, the conclusion talks about the effectiveness of the legislation, the fact supported by B does not affect it.

C) Consuming tobacco products is the only way an adolescent can develop mental abnormalities.
This is not true. Reducing the usage of tobacco among teenagers would curb the problem even if tobacco is not the only cause of mental abnormalities.

D) Most adults would refuse to purchase tobacco products for their teenager friends.
CORRECT: if the legislation is approved but teenagers still consume tobacco products purchased by adults, this problem will not be solved.

E) The regular consumption of tobacco products by teenagers does not produce such beneficial effects as increased confidence and maturity.
The text talks about the "mental abnormalities" problem, and the conclusion shows us a way to reduce it.
Beneficial effects do not affect the effectiveness of the legislation that wants to reduce negative effects of tobacco.

IMO D