A stall warning is activated during flight and the pilot immediately takes action to restore the IAS. This would be an example of

I feel something like this is almost a trick question as it's not immediately obvious if they are asking about the stall warning device or the action taken, given that both items are considered countermeasures of different types..

Or is that just me... Many of these TEM questions seem very much up to interpretation unless you work out how to interpret them they way they are intended to be. Luckily while I got this one wrong, I believe I have enough of a grasp of the concepts to get through the exam tomorrow. Fingers crossed, I'll let you know how I go.