The doubly splice mRNAs produced by HIV do not contain the Rev Response Element (RRE).Which of the following explains why they are transported out of the nucleus without the help of the Rev protein?

A) They interact with the small subunit of the ribosome, which transport them out of the nuceus
B) They lack the cis-acting repressive sequences.
C) The exportin protein binds directly to the mRNAs to transport them.
D) The inportin protein binds directly to the mRNAs to transport them.
E) The HIV Rev protein is still required for their export, but it binds to the poly(A) tail instead of the RRE.