80% of the government revenue from the tobacco sector comes from cigar

Hi,

Probably you can also think of solving this question mathematically.
Revenue = (Cost of Cig) x ( Number of users) x (Average Cigs).

There can be various other various, but let's go ahead with these 3.

Option C states 'The average number of cigarettes smoked per smoker did not decrease significantly last year than the year before.'

We can use the negate rule to test if this is the assumption or not. In the original form, it says the average number of cigs smoked per smoker did not decrease. If that's the case, then according to the formula that we have, the third variable remains the same for last year and the year before. The premise mentions that Tax was dropped, so the cost could have dropped too. In that case the number of users, increases, thus satisfying the conclusion.

If we negate the statement, we get 'The average number of cigarettes smoked per smoker did decrease significantly last year than the year before'. If it did decrease, then too, it's supporting the conclusion saying that the number of users increased.

Since in both the cases, Option C is supporting the conclusion, it fails the negation test.

Now, the easiest way to eliminate Option C is that we just can't assume that price of cigs will go down because tax was decreased. It's wrong to assume a Necessary condition with a sufficient one.

Decreasing tax can/may not have any affect on the price. If the company itself decides to hike the prices, a tax reduction might not bring the price down. This is what comes out properly in the Option B.