Movement of muscles during inspiration allows expansion of the lungs and thus, a

Movement of muscles during inspiration allows expansion of the lungs and thus, a decrease in internal lung pressure (decrease in alveoli pressure) resulting in air entering into the alveoli. Which of the following statements describes what makes this possible?
 Contraction in the rib and neck muscles creates a vacuum in the primary bronchi, which fill with air from the always-open trachea and forces that air down into the alveoli. 
 Contraction in the rib and neck muscles creates a vacuum in the trachea, which fills with air and forces that air down into the alveoli. 
 Pleural fluid surrounding the lungs causes the lung walls to stick to the thoracic wall. 
 The alveoli are located around the periphery of the lungs, and they stick to the thoracic wall.