When studying a plant's protein production, a scientist found two different proteins. The first one contained amino acids from exons 1, 2, 3, 4, 5, and 6, while the second one only contained amino acids from exons from 1, 2, and 3. Which of the following is MOST likely responsible for this difference?
A) a mutation in the gene that encodes an miRNAB) posttranslational modificationC) RNA editingD) alternative RNA processingE) a mutation in the gene that encodes a snoRNA