Shown below is a schematic drawing of a gene, with the transcription unit divided into numbered regions. The arrows (;) indicate transcription initiation sites, "D" indicates a splice donor site, "A"...

Shown below is a schematic drawing of a gene, with the transcription unit divided into numbered regions. The arrows (;) indicate transcription initiation sites, "D" indicates a splice donor site, "A" indicates a splice acceptor site, and "An" indicates a polyadenylation signal. Give all the possible fully processed mRNAs that could be produced from transcripts of this gene (you don't need to draw anything, just list the regions that would be included in each mRNA by number).