Final answer:
The nurse should respond with option d) "Late periods can be caused by stress or hormonal changes." By providing this information, the nurse is acknowledging the client's concerns while also offering possible explanations for the delay in her menstrual period.
Step-by-step explanation:
The nurse should respond with option d) "Late periods can be caused by stress or hormonal changes." This is an appropriate and factual response because late periods can indeed be caused by factors such as stress or hormonal imbalances, not just pregnancy. By providing this information, the nurse is acknowledging the client's concerns while also offering possible explanations for the delay in her menstrual period.