For each of the following, explain whether the rate structure is progressive, proportional, or regressive:
a. Plymouth County imposes a 5% tax on all retail sales in the county. Taxpayers
with incomes less than $12,000 receive a refund of the tax they pay.
b. The country of Zambonia imposes a 10%tax on the taxable income of all individuals.
c. Regan County imposes a property tax using the following schedule:
Assessed Value Tax
$ -0- to $10,000 ... $ 40
$10,001 to $40,000 .. $ 40 + 1% of the value in excess of $10,000
$40,001 to $80,000 .. $ 340 + 2% of the value in excess of $40,000
$80,001 and above ... $ 1,140 + 3% of the value in excess of $80,000

d. The city of Thomasville bases its dog licensing fee on the weight of the dog per the following schedule:
Weight (in pounds) Tax Rate
0 to 40 ........... $ 2 + 50% of weight
41 to 80 ............ $22 + 40% of weight in excess of 40 lbs.
81 and above .......... $36 + 30% of weight in excess of 80 lbs.