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: Surgery
Which of the following is/are clinical features of tetanus? 
Select and explain. 
A. Dysphagia, B. Risus sardonicus, C. Opisthotonus, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: The clinical features of tetanus are: 

Trismus combined with pain and stiffness of neck, abdomen and back.
Dysphagia.
Anxious expression (risus sardonicus).
The muscles of neck and trunk become rigid and the back is slightly arched (opisthotonus).
Respiratory failure.