I am not sure about the source of the original note, but here is the correct option in the two UW questions in the tags (Step one not Comlex) both qs talk about the pathophysiology
"Endothelial dysfunction"
"Hyperreactivity of vascular smooth muscle"
Here is the text from UW explanation "Symptoms of vasospastic angina are thought to be triggered by excess vagal tone, and they occur most commonly at night when vagal tone is at a peak."
"a deficiency of endothelial nitric oxide in affected patients causes increased vagal tone to instead trigger vasoconstriction and precipitate vasospastic symptoms"
So i tried to make the pathophysiology more relevent to the text and explains why it happens during night, and add terms that can be helpful to answer the questions
Source: UWorld - Step 1 38