Tax Schemes and Progressivity Types

Steps:

• Recall definitions: proportional taxes have constant rates across income levels; progressive taxes increase with income; regressive decrease with income.
• Examine diagram: X, Y, Z lines show flat tax amounts or rates unchanging with income brackets.
• Compare schemes: all maintain uniform tax burden relative to income, indicating no slope variation.
• Conclude uniformity: no evidence of increasing or decreasing rates, so all proportional.

Why B is correct:

• Proportional taxes apply the same rate to all income levels, matching the diagram's flat profiles for X, Y, and Z.

Why the others are wrong:

• A: X and Z both flat, so neither progressive; no rate increase in X over Z.
• C: All three show constant rates, not just Y.
• D: Y and Z both flat, so neither regressive; no rate decrease in Z over Y.

Final answer: B