Critical Reasoning

Certain messenger molecules fight damage to the lungs from noxious air by telling the muscle cells encircling the lungs' airways to contract. This partially seals off the lungs. An asthma attack occurs when the messenger molecules are activated unnecessarily, in response to harmless things like pollen or household dust.
Which of the following, if true, points to the most serious flaw of a plan to develop a medication that would prevent asthma attacks by blocking receipt of any messages sent by the messenger molecules referred to above?
(A) Researchers do not yet know how the body produces the messenger molecules that trigger asthma attacks.
(B) Researchers do not yet know what makes one person's messenger molecules more easily activated than another's.
(C) Such a medication would not become available for several years, because of long lead times in both development and manufacture.
(D) Such a medication would be unable to distinguish between messages triggered by pollen and household dust and messages triggered by noxious air.
(E) Such a medication would be a preventative only and would be unable to alleviate an asthma attack once it had started.

IMO D.

Will share explanation if correct.

IMO (D)

(A) Researchers do not yet know how the body produces the messenger molecules that trigger asthma attacks. --> Not interested in how the messenger molecules are produced. We need to make sure that the difference between a false attack and a real one is understood by the molecules.

(B) Researchers do not yet know what makes one person's messenger molecules more easily activated than another's. --> Out Of Scope again. We are not comparing one's rate with another.

(C) Such a medication would not become available for several years, because of long lead times in both development and manufacture. --> Ok. Thank you for the info. No.

(D) Such a medication would be unable to distinguish between messages triggered by pollen and household dust and messages triggered by noxious air. --> Perfect, as explained in A.

(E) Such a medication would be a preventative only and would be unable to alleviate an asthma attack once it had started. --> Point here is about prevention, not about cure.

IMO D .

The medication should be able to diffrentiate between harmful and not-harmful materials , if not then it will hamper the natural defence system . Medication should be to save from unwanted attack but that doent mean that it should be on the cost of exposing the person to all forms of danger such as noxious air .

I doubt in the actual test that questions will this straight. Can someone help me rank this question.