Final answer:
The conductive zone includes the trachea and bronchi which provide pathways for air to enter and exit the lungs; the alveoli are not included as they are part of the respiratory zone where gas exchange occurs. The option (B) is correct.
Step-by-step explanation:
The conductive zone within the respiratory tree includes structures that are not directly involved in gas exchange but provide passageways for the air to travel into and out of the lungs. These structures include the nasal cavity, pharynx, trachea, bronchi, and most bronchioles.
The alveoli, on the other hand, are part of the respiratory zone where the actual gas exchange occurs between the air and the blood. The respiratory zone starts with the respiratory bronchioles, which lead to the alveolar ducts and then to the alveolar sacs. Therefore, the correct answer to the question is B) Trachea and bronchi.