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: ENT
True about Eustachian tube is / are -a) Size is 3.75 cmb) Cartilagenous 1/3 & 2/3rd bonyc) Opens during swallowingd) Nasopharyngeal opening is narroweste) Tensor palati helps to open it 
Select and explain. 
A. acd, B. bde, C. ace, D. ade
C: ace
Answer: C: ace 
Explanation: None