Final answer:
To determine effective gross income, one would deduct a vacancy and collection loss factor from the gross income.
Step-by-step explanation:
Effective gross income is calculated by deducting certain expenses from the gross income. In this case, the correct deduction from gross income to determine effective gross income would be d. A vacancy and collection loss factor. This factor takes into account expected vacancies and losses in rental income, which are subtracted to give a more accurate representation of income.