The "D" in the code 4D indicates that this distribution is from a nonqualified annuity, not from an IRA. Marking the IRA/SEP/SIMPLE box on the form would be contradictory to the code D. Form your most recent post, perhaps you've already realized this.
Why do you think that TurboTax thinks that your wife is receiving this as a result of her employment? Your wife's (or her mother's) employment is irrelevant to anything regarding this distribution.
