问题如下：
Followings are several observations about annuities, how many of them are correct?
I. With immediate fixed annuities, an individual trades a sum of money today for a promised income benefit for as long as he or she is alive.
II. The income yield for a life-only immediate annuity is lower for an older people than for a younger people.
III. Both deferred and immediate annuities provide the same flexibility concerning access to income benefit.
选项：
A.I only
B.I&II
C.All of them are correct
解释：
A is correct.
考点：Annuities
解析：I. 第一个observation的说法是正确的。
II. 对于life-only immediate annuity来说，预期寿命越短，年金income yield越高。因此，相比年轻人，老年人的收益会更高。
III. 延期年金是指保险合同成立生效后且被保险人到达一定年龄或经过一定时期后，保险人在被保险人仍然生存的条件下开始给付年金的年金保险, 而即期年金是指在投保人缴纳所有保费且保险合同成立生效后，保险人立即按期给付保险年金的年金保险。
老师您好，关于III，想向您我下面的理解是否正确：
immediate 的income benefit 更加flexible。因为immediate是一次性付清保费，同时马上开始拿到年金 / income benefit，不用等待一段时间，所以income benefit更加flexible。
非常感谢:)
