Step 1: Concept
Splicing is the process of removing non-coding regions (introns) from an RNA transcript.
Step 2: Meaning
Self-splicing means the RNA molecule itself catalyzes the removal of its own introns without the need for external protein enzymes.
Step 3: Analysis
Molecules composed of RNA that exhibit catalytic (enzymatic) activity are called ribozymes. Group I and Group II introns are famous examples of ribozymes because their folded RNA structure provides the active site for the transesterification reactions needed for splicing.
Step 4: Conclusion
Since the RNA is the catalyst, self-splicing introns are classified as ribozymes.
Final Answer: (B)