Drug use among teens concerns many people in California. Advocates of

E is the correct ans.
B states that drug use in those 5 counties has been dropping steadily for over a decade (10yrs). However, the "SDN" program was implemented only last year. So, there might be other reasons, initiated over 10yrs ago, for the drop in drug use.

In answer E we need to pay close attention where it says "dropped more", as it is referring to "the percentage of teenagers who reported using drugs" . I think it is key on choosing this answer over the other ones.

Which of the following statements, if true, would most strengthen the argument of the advocates of “Stop Drugs Now” that the program should be expanded statewide?

B and E are the only relevant choices among the given ones.

E is more direct and closer to the premise, comparing last year's percentage to the overall decade's percentage.

While B states a steadily drop in drugs user. Steady is a neutral and soft word. Steady can be 1 in 1000 every year or 20 in 1000 every year. So not a
good choice

A. School programs are far less important than parental messages in influencing a teenager’s decision to use drugs.

B. Drug use among teens in the five counties where the “Stop Drugs Now” program was piloted has been dropping steadily for over a decade.

C. Teenagers at the public schools where the “Stop Drugs Now” program was piloted reported higher average levels of drug use than did teenagers at private schools in the same counties where the program was not piloted.

D. There is evidence that teenagers who start smoking at an early age are more likely to experiment with illegal drugs than teenagers who do not smoke.

E. The percentage of teenagers who reported using drugs at the schools where the “Stop Drugs Now” program was piloted dropped more in the last year than in any other year over the last decade.

Which of the following statements, if true, would most strengthen the argument of the advocates of “Stop Drugs Now” that the program should be expanded statewide?

A. School programs are far less important than parental messages in influencing a teenager’s decision to use drugs. (irrelevant)

B. Drug use among teens in the five counties where the “Stop Drugs Now” program was piloted has been dropping steadily for over a decade. (this weakens the statement, as if the rate of drug use was already dropping then the "Stop Drugs Now" program is not needed in the first place, let alone the program being expanded to cover all of California).

C. Teenagers at the public schools where the “Stop Drugs Now” program was piloted reported higher average levels of drug use than did teenagers at private schools in the same counties where the program was not piloted. (Opposite Effect).

D. There is evidence that teenagers who start smoking at an early age are more likely to experiment with illegal drugs than teenagers who do not smoke. (Irrelevant to the argument and the question stem).

E. The percentage of teenagers who reported using drugs at the schools where the “Stop Drugs Now” program was piloted dropped more in the last year than in any other year over the last decade. (this is the OA as the program helped reduce drug usage after it was introduced.)

The OA is E

options A, C & D can be easily eliminated.

Option B says "Drug use among teens in the five counties where the “Stop Drugs Now” program was piloted has been dropping steadily for over a decade" but the programme itself started last year. it means the programme, which was started last year has nothing to do with it. Reject

E is the clear winner.