Helga and Rudiger have decided that, with a growing family and stable employment incomes, the time is right to purchase a life insurance policy. The amount of life insurance on Helga's life needed to provide a suitable income for the surviving family does NOT depend on which of the following? a) Helga's after-tax income Ob) the survivors' pre-tax investment returns Oc) the survivors' average and marginal tax rates d) the survivors' other sources of income