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 likely to cause obstructive shock? 
Select and explain. 
A. Myocardial infarction, B. Dysrhythmia, C. Tension pneumothorax, D. Valvular heart disease
C: Tension pneumothorax
Answer: C: Tension pneumothorax 
Explanation: Common causes of obstructive shock include cardiac tamponade, tension pneumothorax, massive pulmonary embolus and air embolus.