Took Some time for me to understand. But I feel all the cases other than choice C fails to stand in this scenario.
Lets see what the averaging method says.
Let income for last three years be a, b,c and current year d.
First and foremost thing, to apply this method, a tax payer's current year income should have satisfied the below case.
\(d > 1.4(\frac{(a+b+c)}{3})\)
If this method is applied then, taxpayer will pay less tax than state's current tax majors.
Now the questions stem says, In case if this method was not adapted, which of the following criteria would seriously would have affected?
Choice A - If the income of a person is steadily decreased, the the current year's income will be less than the average. Hence even this policy would be in force, this person was not eligible for income averaging.
Choice B - Even if the income has increased by 50% 4 years ago, we are considering the last 3 year's income which is same. So this person is also not eligible for the method.
Choice D - If this year's income is 0, the person is also not eligible
Choice E - If a person is retired, his current year's income would be 0.
Only choice C says Current year's income is doubled so this person is eligible for the policy. So this person will get benefit of it. If this policy was not in force, the person would be affected.