The Paco₂ decreases when:

A)Alveolar ventilation and CO₂ production are increased and dead space is increased.
B)Alveolar ventilation is decreased,CO₂ production is unchanged,and dead space is increased.
C)Alveolar ventilation is increased and CO₂ production and dead space are decreased.
D)Both alveolar ventilation and CO₂ production are decreased and dead space is increased.