Final answer:
The nurse should administer the patient's insulin injection at 11:15 (option B)
Step-by-step explanation:
The nurse should administer the patient's insulin injection at 11:15 (option B) based on the patient's medication administration record and the arrival time of the lunch tray at 11:45. Regular insulin is typically administered 30 minutes before a meal to allow the insulin to start working as the blood sugar level rises after eating. This ensures that the insulin is effective in bringing the blood sugar levels back to normal.