Micro RNAs (mi RNAs) are a class of non-coding RNAs that play important role in the regulation of gene expression. One single miRNA usually targets many genes and one gene might be regulated by multiple miRNAs. The reason for multiple targets is:

• A. miRNA binding sites included not only 3′UTRs but also 5′UTRs and CDSs.
• B. short base pairs within miRNA-3′UTR duplex
• C. Both a and b
• D. None of the above