Identify which of the following regular tax amounts create AMT preferences.
a. Depletion expense.
b. Employee's exclusion for an employer's contribution to the employee's pension plan.
c. Incentive stock option exercise.
d. Student loan interest expense.
e. Excess of accelerated over straight-line depreciation on real property placed in service before 1987.
f. Exclusion for gains on the sale of certain small business stock.
g. Medical expenses.