Final answer:
The principal part of the mortgage payment is not considered a tax deduction on an itemized return, unlike mortgage interest, home equity interest, and real estate property tax.
Step-by-step explanation:
The item on the list that is NOT considered a tax deduction on an itemized return is c. mortgage payment. While both mortgage interest and home equity interest, if it is used to buy, build, or substantially improve the taxpayer's home, can be deducted, the principal part of the mortgage payment itself is not deductible. Similarly, real estate property tax may also be deducted under the itemized deductions when filing a tax return.