The following problems involve a transfer by D to the T Trust Co. trustee, on the following alternative terms. What are the estate tax consequences upon D's death?

a) Income to D for life, remainder to A and B equally or to their estates.

b) Income to D for life, payable once a year on December 1, remainder to A or A's estate, provided that no part of the income accruing between the last December 1 payment and D's death shall be paid to D, but it shall be added to corpus.

c) Income to D for 15 years, remainder to B or B's estate. D died after 14 years.

d) Income to D for 15 years, remainder to B or B's estate. D died after 17 years.

e) Income to A for life, then D for life, remainder to B or B's estate. D predeceases A.

f) Income to W for life, remainder to D if living, otherwise to S if then living. D predeceases W and S.

g) Income to W for life, remainder to D if living, otherwise to S. D predeceases W and S.

h) Income to A for life, provided D does not direct payment to someone else, remainder to B life living, otherwise to A's estate. D dies during A's lifetime.

i) Income to W for life, then to A or B for life as D may direct, remainder to z. D predeceases W, A, and B.

j) Income to A for life, remainder to B or B's estate. D reserves the right to instruct T to pay income to B. D predeceases A and B.

k) The first $100,000 of income to D, then income to A for life, remainder to B. D died after payment of $90,000.