When using a vaporiser outside a circle system (VOC):
a) the vaporiser is usually temperature-compensated
b) the temperature of the agent in the vaporiser rises with an increase in fresh gas flow
c) the vapour pressure of the agent is inversely proportional to the temperature
d) the inspired concentration of the volatile agent is a function of alveolar ventilation
e) the alveolar concentration is a function of pulmonary perfusion.