11(1)A derivative pension for the benefit of the spouse of a retiring officer shall, according as the retiring officer may, in conformity with rules under paragraph 10 above, elect, be payable either—
(a)in respect of the period, if any, for which the spouse survives the retiring officer, or
(b)in respect both of the period of their joint lives (from the date of retirement) and of the period, if any, for which the spouse survives the retiring officer,
and the rules may provide for the pension under paragraph (b) above to be at one rate during the joint lives, and at a higher rate thereafter.
(2)A derivative pension for the benefit of a dependant (not being the spouse) of a retiring officer shall be payable for the period, if any, for which the dependant survives the retiring officer.