Relaxation of the diaphragm and intercostal muscles leads to which of the following?

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Relaxation allows the chest to recoil inward. When the diaphragm and intercostal muscles relax, the elastic tissues of the lungs and chest wall pull the thoracic cavity toward a smaller volume. As the volume decreases, intrapulmonary pressure rises above atmospheric pressure, so air is pushed out. So the correct idea is that the thoracic cavity becomes smaller and the pressure increases during relaxation. The other possibilities don’t fit because relaxing the inspiratory muscles does not expand the cavity, does not produce no change, and does not lower the pressure.