A tax of $15 on an income of $200,$10 on an income of $300,and $8 on an income of $400 is:

A) constant-rate.
B) proportional.
C) progressive.
D) regressive.

Constant-rate

A process or condition that occurs at a steady, unchanging rate over time.

Regressive

Regressive, in economic terms, often refers to a tax system where the tax rate decreases as the taxable amount increases, imposing a greater burden on lower-income individuals.