问题如下：
Based on Exhibit 1 and the method XYZ uses to link pension benefits to salaries, the change in the compensation growth rate compared with the prior period will most likely result in:
选项：
A.lower periodic pension cost.
B.no change in the periodic pension cost.
C.higher periodic pension cost.
解释：
A is correct.
A decrease in the assumed future compensation growth rate will decrease a company’s pension obligation when the pension formula is based on the final year’s salary. Lowering the assumed future compensation growth rate decreases the service and interest components of periodic pension costs because of a decreased annual unit credit.
解析：A选项正确。题干说XYZ公司未来支付给员工的养老金是基于员工退休前最后一年的薪酬水平的。如果对员工未来薪酬增长率的假设比原来低了，会直接降低最后一年的薪酬，基于final salary计算出的annual unit credit也降低，annual unit credit折现后算得的current service cost以及相应的利息费用都减少，periodic pension cost降低。
我理解表格中的future compensation growth rate是同一时间轴上的，prior period是前一期的，current period是当期的。例如前一期期初的salary是100，prior period growth rate3%，current period growth rate是2.5%，则下一期的salary是100*（1+3%）*（1+2.5%）=105.575，因为计算 current service cost用的是final salary，所以前面不管增长率怎么变，prior period 和 current period的current service cost都是用相同的unit credit计算，除了折现时间不同，其他的应该都一样，这样理解问题出在哪里。
