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: Anaesthesia
A patient was admitted epidural anaesthesia with 15 ml of 1.5%. Lignocaine with adrenaline for hernia surgery. He devoled hypotension and respiratory depression within 3 minutes after administration of block. The most common cause would be: 
Select and explain. 
A. Allergy to drug administered, B. Systemic toxicity to drug administered, C. Patient got vasovagal shock, D. Drug has entered the subarachnoid space
D: Drug has entered the subarachnoid space
Answer: D: Drug has entered the subarachnoid space 
Explanation: D i.e. Drug has entered the sub arachnoid space