C

Vasomotor reversal of Dale occurs when an α-adrenoceptor blocker (e.g., phentolamine) is given first; subsequent adrenaline then produces vasodilatation and a fall in blood pressure (with reflex tachycardia) because its β2-actions are now unopposed. The only option that places an α-blocker before adrenaline is C, which therefore best represents this phenomenon [Burn & Rand 1958, PMID 13618554; Okada 2017, PMID 28982383].