Which one is the smallest RNA?

Answer: Option B

tRNA is the smallest RNA among the 3 types of RNA, possessing around 75 - 95 nucleotides.
tRNAs are an essential component of translation, where their main function is the transfer of amino acids during protein synthesis. Therefore, they are called transfer RNAs.
Transfer RNA (tRNA) has a long-established role in protein synthesis. The tRNA molecule serves as an adaptor between the genetic instructions written in nucleic acid sequences and the protein products encoded in genes.