19. Which mechanism BEST explains how antisense RNA can inhibit gene expression through RNA-RNA duplex formation?
(A) The antisense RNA recruits general transcription factors to block RNA polymerase binding at the promoter.
(B) The RNA-RNA duplex formation interferes with splicing by masking splice sites on the DNA template within the intron.
(C) RNA-RNA duplex formation increases RNA polymerase II processivity, leading to increased transcription of the target gene.
(D) The RNA-RNA duplex recruits Argonaute proteins to trigger endonucleolytic cleavage of the sense mRNA in the nucleus.
(E) Duplex formation blocks the ribosome-binding site or start codon on the sense mRNA, preventing translation initiation.