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: Physiology
true is all except regarding intrafusal fibres 
Select and explain. 
A. Nuclear bag fibres are lesser, B. Nuclear chain fibres are shorter and thinner, C. Secondary endings excited by chain fibres only, D. Primary endings excited by bag fibres only
D: Primary endings excited by bag fibres only
Answer: D: Primary endings excited by bag fibres only 
Explanation: None