In terms of the tax formula applicable to individual tax payers which of the following statements if any are true?

a. In arriving at taxable income a taxpayer must chose between the standard deduction and itemized deductions

b. In arriving at taxable income a taxpayer must elect between claiming deductions for AGI and deductions from AGI

C. In arriving at AGI a taxpayer must elect between claiming deductions for AGI and deductions from AGI

d. In arriving at AGI deduction for qualified business income is subtracted from gross income

e. None of these

please explain !