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
All are true about Thiopentone except: 
Select and explain. 
A. NaHCO3 is a preservative, B. Contraindicated in Porphyria, C. Agent of choice in shock, D. Has cerebroprotective action
C: Agent of choice in shock
Answer: C: Agent of choice in shock 
Explanation: C i.e. Agent of choice in shock Thiopentone, a pale yellow powder, is ultrasho acting smooth inducing agent because of rapid redistributionQ. It is used in 2.5% conc. at 2.5 - 4.5 mg/kg mixed with 6% anhydrous Na2CO3 as perservativeQ Thiopentone is contraindicated in porphyria, status asthmaticus, severe shock, pericardial temponade and uncompensated myocardial diseaseQ