Final answer:
Personal gifts and inheritances are not included in the computation of total income on the Form 1040.
Step-by-step explanation:
The item that is not included in the computation of total income on the Form 1040 is d) Personal gifts and inheritances. Rental income, investment income, and salary and wages are all included in the computation of total income. Personal gifts and inheritances are generally not considered taxable income and therefore do not need to be reported on the Form 1040.