The correct answer is B. 120 degrees.
The central angle of a sector is the angle
formed by the two radii that intersect at the arc of the sector. The ratio of the central angle $\theta$ to $360^\circ$ is equal to the ratio of the arc length $s$ to the circle’s circumference $c$. In this case, the arc length is the amount of income tax paid, and the circle’s circumference is the total income.The average income tax rate in the United States is 22%. If we assume that the average income is $50,000, then the amount of income tax paid is $11,000. The circumference of a circle with radius 50 is $2\pi r = 2\pi (50) = 314.159$. Therefore, the central angle of the sector representing income tax is $\theta = \frac{s}{c} \times 360^\circ = \frac{11,000}{314.159} \times 360^\circ \approx 120^\circ$.
Option A is incorrect because it is the central angle of a sector representing 10% of the total income. Option C is incorrect because it is the central angle of a sector representing 15% of the total income. Option D is incorrect because it is the central angle of a sector representing 20% of the total income.