218.41—When a child annuity ends.
A child annuity ends with the earliest of—
(c)
The last day of the month before the month in which the child attains age 18 if the child is not eligible for an annuity as a disabled or student child;
(d)
The last day of the last month in which the child is considered a full-time student, as defined in part 216 of this chapter, if the child is a full-time student age 18 through 19; or
(e)
The last day of the second month after the month in which the child's disability ends, if the child is over age 18.