What is interesting about the promoters that direct transcription of the Class II and Class III genes from bacteriophage T7?

A) They are very rich in GC basepairs.
B) They are much longer and more complex than the host gene promoters.
C) They can only be recognized by the viral RNA polymerase.
D) They can be recognized by either the host or viral RNA polymerase.
E) They are not very highly conserved.