Which description applies to alternative mRNA splicing?A-protein modifications such as addition of a functional group, or structural changes such as foldingB-heritable changes in gene expression that occur without altering the DNA sequenceC-a gene cluster controlled by a single promoter that transcribes to a single mRNA strandD-mRNA modifications such as additions of a 5'-cap and 3' poly-A tail and removal of intronsE-processing of exons in mRNA that results in a single gene coding for multiple proteins