Choice "D" is correct. The DIF generally selects for audit returns of individuals with gross incomes greater than $100,000, not $50,000.Choice "b" is incorrect. The DIF selects for audit returns of self-employed individuals with substantial business income and deductions.Choice "a" is incorrect. The DIF selects for audit returns of cash businesses (because cash income is easier to conceal).Choice "c" is incorrect. Returns of individuals whose itemized deductions are in excess of norms established for income levels are often selected for audit.