This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
All of the following statements about Ribozymes are false, EXCEPT: 
Select and explain. 
A. They are DNA molecules, B. They are not present in ribosomes, C. They plays a key role in RNA synthesis, D. They play a key role in post-transcriptional conversion of pre-mRNA to mature mRNA
D: They play a key role in post-transcriptional conversion of pre-mRNA to mature mRNA
Answer: D: They play a key role in post-transcriptional conversion of pre-mRNA to mature mRNA 
Explanation: Ribozymes are RNAs which exhibit highly substrate specific catalytic activity. They play a key role in the intron transcripts excision and exon transcripts splicing events essential for the conversion of pre mRNA to mature mRNA. Ribozymes catalyzed transesterification, and ultimate hydrolysis of phosphodiester bonds in RNA molecules. Ref: Textbook Of Medical Biochemistry (3Rd Edn.) By S. Ramakrishnan page 338.