Final answer:
Mary's receipt of $15,000 from a personal loan should be excluded from gross income because it is a debt that must be repaid, not income.
Step-by-step explanation:
The question pertains to whether Mary's receipt of $15,000 from the bank for a personal loan should be included in or excluded from gross income. When creating a budget or filing taxes, it is important to distinguish between taxable and non-taxable income. According to basic concepts of taxation, loan proceeds are not considered income because they represent a debt obligation that must be repaid. Therefore, the loan amount received by Mary does not count as income and should not be included in her adjusted gross income when calculating taxable income. Taxable income is typically derived from wages, interest, and government support, but excludes loans since they are not earnings but rather amounts that will need to be paid back to the lender.