There is a married couple with three children and an annual income of $24,000 who, because of the standard deduction and personal exemptions, owe no federal income tax. Suppose the child tax credit is such that for families that pay less income tax than the child credit to which they are entitled the law allows them to receive a refund of 15% of earnings over $12,000, up to a maximum of $800. a. What is the familys tax credit per child? b. Suppose the cap is raised to 25%. What is the familys tax credit per child in this scenario? c. Suppose that instead of raising the cap, i.e. the cap remains 15%, the threshold is lowered to $4,000. What is the familys tax credit per child in this scenario? d. Which change, raising the cap to 25% or lowering the threshold to $4,000, would lead to more families qualifying for the tax credit?