This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Clinical Trials, Subject name: Pharmacology
Therapeutic drug development which is the newest agent - 
Select and explain. 
A. Ribozyme, B. Micro RNA, C. SnRNA, D. Retro RNA
B: Micro RNA
Answer: B: Micro RNA 
Explanation: Ans. is 'b' i.e., Micro RNA o Mi RNAs regulate gene expression by pairing to target mRNAs, thus inducing translational repression,o Novel findings indicate an orchestrated coregulation with long noncoding RNAs.o Since its discovery, this small RNA species has opened new frontiers in cardiovascular diseases.