Which of these is not a type of RNA?

Question

Which of these is not a type of RNA?

Quizplus · Accepted Answer

Ribonucleic acid (RNA) is one of the three major biological macromolecules that are essential for all organisms along with DNA and proteins.
There are four types of RNA:
Messenger RNA (mRNA)  carries codes from the DNA in the nucleus to the sites of protein synthesis in the cytoplasm (the ribosomes). 
Transfer RNA (tRNA) which brings protein sub-units (amino acids) to ribosomes during translation.
Ribosomal RNA (rRNA) which together with ribosomal proteins, makes up the ribosomes, the organelles that translate the mRNA. 
Small nuclear RNA (snRNA) which together with proteins, forms complexes that are used in RNA processing in eukaryotes. (These are not found in prokaryotes).

Which of These Is Not a Type of RNA