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: Dental
Type of filler particle used in packable composite: 
Select and explain. 
A. Fibrous filler particles, B. Microcrystalline filler particles, C. Mixture of both, D. None of the above
A: Fibrous filler particles
Answer: A: Fibrous filler particles 
Explanation: Specifically the packable/condensable characteristics are derived from the inclusion of elongated, fibrous filler particles of about 100 µm in length and/or rough-textured surfaces or branched geometries that tend  to interlock and resist flow.
Phillips Dental materials 12th edition pg no 286