It has been recently determined that the gene for Duchenne muscular dystrophy (DMD) is more than 2000 kb (kilobases) in length; however, the mRNA produced by this gene is only about 14 kb long. What is a likely cause of this discrepancy?

A) The DNA represents a double -stranded structure, whereas the RNA is single -stranded.
B) The introns have been spliced out during mRNA processing.
C) More amino acids are coded for by the DNA than by the mRNA.
D) The exons have been spliced out during mRNA processing.
E) When the mRNA is produced, it is highly folded and therefore less long.