Which symptom would most likely occur from both morphine and nitroglycerin?

Both morphine and nitroglycerin can lead to a range of side effects, and all the symptoms listed — dizziness, nausea, and hypotension — can occur as a result of using these medications.

Morphine, an opioid analgesic, can cause dizziness due to its central nervous system effects, and it may also lead to nausea as a side effect, particularly in individuals who are not accustomed to opioids. Furthermore, morphine can cause hypotension by inducing vasodilation and reducing systemic vascular resistance.

On the other hand, nitroglycerin is a vasodilator typically used to treat angina and heart failure. It works by relaxing blood vessels, which can lead to a decrease in blood pressure, resulting in hypotension. Dizziness can also occur due to reduced cerebral perfusion associated with decreased blood pressure, and nausea can happen due to the vasodilatory effects that may disturb the gastrointestinal system or as a result of other associated effects like headache and transient low blood pressure.

Since all three symptoms can occur due to the effects of both medications, the most comprehensive answer is that all of the symptoms listed are likely to occur from either morphine or nitroglycerin, making "All of the above" the correct choice.