Answer: a. The marginal tax rate increased from 2009 to 2010.
Step-by-step explanation:
The marginal tax rate refers to the taxes that people have to pay on any additional dollar that they make.
In the year 2009 this rate was 15% but in 2010 this rate went up to 20% across the board including for the person earning $35,000. This shows a clear increase in the marginal tax rate between both years.