Answer:
All of the above are ways in which mRNA can be processed.
Step-by-step explanation:
DNA is transcribed into pre-mRNA which is further processed into mature mRNA. mRNA be processed by various ways: as at the 5' end of RNA, addition of capping occurs, and at the 3' end, there is addition of large number of adenosine ( approx 200), known as polyadenylation.
RNA splicing is the process of removal of introns and of addition of exons, through which only coding sequences (exons) remain in the mature mRNA and non coding regions(intron) are removed.
Alternative splicing may produced various type of mRNA from a single type of pre- mRNA.