For administering pain medication to Mr. U (lung cancer and pulmonary resection), which route is the nurse most likely to question?

The correct answer is C: Rectal. Administering pain medication rectally may not be suitable for Mr. U with lung cancer and pulmonary resection due to potential issues with absorption and unpredictable drug effects. The lung cancer and pulmonary resection could affect blood flow and absorption through the rectal mucosa. Oral route may be compromised due to nausea or vomiting. IV route provides rapid onset and precise dosing. Intramuscular route may be used but could have slower onset compared to IV. Overall, rectal route is most likely to be questioned due to uncertainties in drug absorption and effectiveness in this specific patient population.