Self splicing introns are found in

Answer: Option B

Self-splicing introns are found in rRNA genes.
Self-splicing occurs for rare introns that form a ribozyme, performing the functions of the spliceosome by RNA alone.
The Tetrahymena pre-rRNA self-splicing intron is shown to function in the unnatural context of an mRNA transcribed by RNA polymerase II in mammalian cells.