Final answer:
The best response for the nurse in this scenario is to contact the primary care provider promptly and report the signs of perforation, a potentially critical situation requiring immediate medical attention.
Step-by-step explanation:
In the case of a patient exhibiting sudden onset of exquisite abdominal tenderness, a spike in temperature, and a rigid abdomen, this could be indicative of a serious and potentially life-threatening complication such as perforation due to diverticulitis. The nurse's best response should be to contact the primary care provider promptly and report these signs of perforation. This would likely require urgent medical intervention to prevent further complications such as peritonitis, which can be life-threatening. Administering an enema, inserting an NG tube, or suspecting an obstruction may not be appropriate without further evaluation by a physician because they could worsen a perforation.