An employer sent his worker to the emergency department after having hit his head on a machine. Examination: normal. What is the single most likely investigation you would do?

The key is A. Reassurance. [Indications for CT are not fulfilled by given criteria for CT. NICE has

mentioned X-ray skull is no more preferred over CT. As no sign of basal or skull fracture no need to do

skull X-ray. Hence answer for this question is D. Reassurance].