This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diabetes Mellitus, Subject name: Medicine
An unconscious 50 year old known case of diabetes mellitus is brought to the ER. His medical records show he is on warfarin for atrial fibrillation. Which of the following investigations will not be done in this patient for work up? 
Select and explain. 
A. Lumbar puncture, B. Random blood sugar, C. NCCT, D. ECG monitoring
A: Lumbar puncture
Answer: A: Lumbar puncture 
Explanation: Option A- Always C/I in bleeding diathesis & in |ICT Option B- Known case of D.M so RBS should be done. Option C- Since he is unconscious may be d/t warfarin toxicity so CT scan is a probable investigation. Option D- patient on warfarin for atrial fibrillation so ECG monitoring is mandatory.