What anatomical structures are included in the upper airway?

The correct choice identifies the primary components of the upper airway, which are the nose, mouth, and pharynx. These structures are crucial for the initiation of respiration as they serve several important functions. The nose is responsible for filtering, humidifying, and warming inhaled air. The mouth provides an alternative pathway for air to enter the respiratory system, especially during vigorous physical activity when airflow demand increases. The pharynx acts as a passageway that connects the nasal and oral cavities to the larynx (part of the lower airway). By encompassing these three structures, the choice accurately reflects the anatomy involved in conducting air before it reaches the trachea and lower airway structures.

In contrast, the other options involve structures that either belong to the lower airway or are part of different respiratory functions, which do not fit the definition of the upper airway.