nitroglycerin 0.4 mg sublingually every 5 minutes, up to 3 doses over 15 minutes
Number 3 is correct.
Acetaminophen is commonly given to relieve mild headache pain, and this is a typical dose. Morphine is an opioid and would not be the first choice, due to the risk of dependency and/or abuse. It may also make the client drowsy, which increases the risk of falls. Aspirin increases the risk of bleeding, especially at doses greater than 81 mg, so this would not be a first choice. Nitroglycerin is given for angina pain, not headaches.