Hello, Jkjones,
It's good to see you're using the Variance Test. It's pretty advanced stuff, and for such a rare question type, many don't bother - but it works.
The problem with answer choice D is that the conclusion isn't really about the attitudes of the low- and middle-income taxpayers. This is a trick that a lot of questions of this sort use. The government is only saying that a tax on luxury items
would result in a substantial revenue increase
while only affecting the people and organizations that purchase luxury items. I don't buy too many Lamborghinis or yachts, myself, for example.
As a result, D isn't super relevant, and is not the best answer choice.
Answer choice C is the important one. Using the Variance Test gives us two possibilities: the sales of luxury items
will occur at current rates once the luxury tax has passed, or they
won't occur at that rate. This would be a Yes/No variance, as opposed to All/None or something like that.
If the answer is Yes, and they will still occur at current rates, then the government's prediction will be accurate - lots of money will flow, nobody else will be affected. But if the answer is No, and they will
not still occur at current rates, then the government's prediction may well be
inaccurate. If people stop buying Lamborghinis because the tax is too high, then not only might the revenue increase might not be substantial, but other people than the wealthy may be affected. Like all the manufacturers of the Lamborghinis, for instance, the people that work in factories to make the parts or tools involved. Or something like that.
Hope that helps,
Lucas Moreau
