You Are Studying Lipoprotein Processing in a Strain of Mutant

You are studying lipoprotein processing in a strain of mutant mice. You find that these mice synthesize the same apolipoprotein composition contained in lipoproteins made in the liver and the intestines, whereas, in wild-type mice there are 2 different sized apolipoproteins in these same tissues. Examination of the mRNA processing in the mutant mice would most likely show a defect in which of the following processes?

A) alternative polyadenylation
B) alternative splicing
C) differential capping
D) posttranscriptional modification converting a U to a T residue
E) RNA editing