A Patient Who Takes Insulin States, "My Blood Glucose Has

A patient who takes insulin states, "My blood glucose has been low the last few mornings." Which statement would the nurse evaluate as a possible cause of this change?

A) "I have been taking a garlic supplement to prevent colds."
B) "I have been taking St. John's wort to help with my memory."
C) "I have been taking extra vitamin C since so many people have influenza."
D) "I have been taking vitamin D to help build up my bones."