Nan Chen works for a firm that offers a benefit plan that guarantees her an annual payment in retirement equal to her average salary over her last 3 years of full-time employment multiplied by 3% for each of her years of full-time employment, as long as she has reached age 62.The most appropriate term for Nan’s retirement plan is a: A.salary-based plan. B.defined benefit plan. C.years-of-service plan.