The taxable portion of a monthly income benefit paid during the annuity phase from a nonqualified annuity is calculated using the

A 1035 exchange allows for the tax-free transfer of funds from one life insurance policy or annuity to another, but it does not pertain to the calculation of taxable income from annuity payments. This option is focused on exchanging policies rather than determining the tax implications of income benefits.

A mortality table is a statistical tool used to estimate life expectancy and the likelihood of death at various ages, which is relevant for life insurance underwriting and annuity pricing. However, it does not relate to the specific calculation of taxable income from annuity distributions.

The 7-pay test is a guideline used to determine whether a life insurance policy is considered a modified endowment contract (MEC), which affects the tax treatment of withdrawals. It does not apply to the calculation of taxable portions of income benefits from annuities and is unrelated to the annuity phase.