The earned income credit: a. Must be calculated on earned income as well as adjusted gross income in some cases. b. Cannot exceed the amount of the tax liability.

The correct answer is letter "A": Must be calculated on earned income as well as adjusted gross income in some cases.

Explanation:

The Earned Income Credit is a refund the government issues to taxpayers in case their earned income or Adjusted Gross Income (AGI) is lower than the amount of taxes they need to pay. The maximum earned income to qualify for an earned income credit also depends on the number of children in the household, and if the file return is submitted jointly.