Step 1: Concept
Condensation polymers are formed by a reaction between monomers with the elimination of small molecules like water or ammonia.
Step 2: Meaning
This differs from addition polymers, where monomers simply link together without losing any atoms.
Step 3: Analysis
Natural rubber, Neoprene, and PTFE (Teflon) are addition polymers formed from unsaturated monomers. Urea-formaldehyde resin is formed through a condensation reaction between urea and formaldehyde.
Step 4: Conclusion
Urea-formaldehyde resin is the correct example of a condensation polymer.
Final Answer: (C)