Which of the following led the largest number of taxpayers to switch from itemizing deductions before 2018 to using the standard deduction in 2018?

a. Their incomes were lower in 2018 than before 2018.

b. Deductions for dependents (exemptions) were eliminated and the standard deduction was nearly doubled.

c. The deduction for medical expenses was reduced by 50%.

d. Marginal tax rates were reduced.

e. No other answer is a reasonable explanation.