A 34 year old woman is brought to A&E after ingesting an unknown quantity of paracetamol about 2 hours ago. She is well and examination is normal. What is the most appropriate immediate investigation to guide further management?ATake a timed plasma paracetamol level at 4 hours post ingestionBPerform urgent CT of the headCMeasure serum liver enzymes immediately onlyDStart N acetylcysteine without any levelsEWait 24 hours and then check a levelCheck my answer