All forms of RNA are intermediate molecules that are fabricated within DNA to perform cellular functions.
mRNA - messenger RNA carries selected portions of DNA used to fabricate polypeptides used to fabricate amino acids for protein.
tRNA - transfer RNA is comprised of select genetic code and transfers amino acids to ribosomes for assembly
rRNA - ribosomal RNA is comprised of select genetic code and makes the ribosomes
RNA is highly mutatable, highly reactive, non-reproductive, and highly specialized metabolically, and consequently totally unsuitable for consideration of any pre-DNA senario being posited for the origin of life.