The Figure Below Show a Simplified Version of the Current

Multiple Choice

The figure below show a simplified version of the current (2015) Canadian federal income-tax system.The marginal income-tax rates for the four ranges of income are 15%,22%,26%,and 29%,respectively. FIGURE 18-2
-Refer to Figure 18-2.What must be true of the four marginal income-tax rates in order for the tax to be considered a "flat" tax?

A) they need to be zero
B) they need to be the same
C) they need to be constant
D) they need to gradually level out
E) they need to be smaller