What is ventilation

  A.  An increase in the hydrogen ion concentration in the interstitial spaces of the  brain stem leads to an increase in the duration of the respiratory cycle (duration  of respiratory cycle equals duration of inspiration plus duration of expiration).

  B.  An increase in the pressure within the chest cavity results in the inspiration of air  into the lungs.

  C.  The problems with ventilation induced by injection of curare occur because of the  drug's direct action on the mAChRs (muscarinic Acetylcholine Receptors) in the  plasma membranes of the diaphragm skeletal muscle and the rib-cage skeletal  muscles.