What distinguishes a defined benefit plan from a defined contribution plan?

Answer: D. A defined benefit plan promises a stated benefit at retirement and the employer contributes what is needed to fund it, while a defined contribution plan fixes what goes into the account and the retirement benefit depends on the account's value. Both are qualified plans established by employers, and deferrals are a feature of particular plan designs rather than the dividing line.Source: IRS Publication 560 — Pub 560, Defined benefit and defined contribution