A system-wide county school anti-smoking education program was institu

Responding to a pm:

First step is to analyze the argument.

Premises:
- A system-wide county school anti-smoking education program was instituted last year.
- Last year, the incidence of students smoking on school premises decreased by over 70 percent.

Conclusion: The program was clearly a success.

Ok, so the conclusion seems a little far fetched, isn't it? Just because the anti-smoking program was instituted last year and the incidence of smoking decreased last year, doesn't necessarily mean that the program was responsible for the decrease. Right? There could another cause. We are assuming that the program was responsible for the decrease.

Look at the options now.

Option (B) The doubling of the price of a pack of cigarettes last year was not the only cause of the student’s altered smoking habits.

We are assuming that the program was the cause of the student's altered smoking habits i.e. some other thing was certainly not the ONLY cause. If there is a confusion, try to negate it.

The doubling of the price was the only cause of the student’s altered smoking habits.

Now our conclusion just cannot hold. If doubling the price was the ONLY cause, the program cannot be responsible for the decrease. Hence (B) is the assumption.

Notice that (E) is not the assumption.
(E) School policy enforcers were less vigilant in seeking out smokers last year than they were in previous years.
If we negate it, we get

School policy enforcers were not less vigilant in seeking out smokers last year

Our conclusion can still hold. The school policy enforcers were the way they are every year or perhaps they were more vigilant, either way, it is still possible that the program is responsible for the decrease in smoking.