Polymer Chemistry

Step 1: Understanding Polyphosphazene Polymers.
Polyphosphazene polymers are a class of materials that have a wide range of biomedical applications due to their unique properties such as biodegradability, biocompatibility, and versatility in structural and functional modifications.

Step 2: Analyzing the Options.
- (A) Polyphosphazene polymers are used as structural materials in biomedical applications, particularly for heart valves and blood vessels due to their flexibility and strength. - (B) Polyphosphazene polymers are also used in drug delivery systems, where their biodegradability allows controlled drug release. - (C) These polymers can be used as biodegradable supports for in vivo bone regeneration, as they can be gradually resorbed by the body while providing mechanical support.

Step 3: Conclusion.
Thus, all of the listed applications (A), (B), and (C) are true for polyphosphazene polymers, so the correct answer is option (3).