Which of the following are basic features of the generation-skipping transfer tax (GSTT)? I. The GSTT cannot apply unless the transferor and transferee are related. II. With an indirect skip, the GSTT will be due at the same time as the gift or estate tax. III. In any transaction to which the GSTT applies, the gift or estate tax will also apply. IV. The GSTT rate is the highest regular estate tax rate in effect at the time of the transfer. ? 1 and 11 only I and IV only ? 11 and 111 only III and IV only