which is a compound-complex sentence?

A. While they were walking on campus, Dwayne admired the buildings and Michelle imagined attending classes in this beautiful place.
B. Daily exercise is beneficial to your health, therefore you must take several precautions to avoid injuries.
C. Our experienced tour guide, who grew up in the area, directed us toward some amazing local scenes.
d. The electronic merchandise was defective, as it had been severely damaged during shipment.