Final answer:
The trachea and bronchial tubes are part of the lower respiratory tract, making option E (Both C and D) the correct answer.
Step-by-step explanation:
The structures located in the lower respiratory tract are the trachea and bronchial tubes. The pharynx is part of the upper respiratory tract, while the larynx marks the entrance to the lower respiratory tract. Therefore, the answer to which of the following structures is located in the lower respiratory tract is E) Both C and D.