Which of the Following Ventilator-Related Factors Have a Major Effect

Which of the following ventilator-related factors have a major effect on metered dose inhaler delivery of aerosolized drugs during mechanical ventilation?
1) Mode of support
2) Presence of positive end expiratory pressure
3) V_T
4) Inspiratory wave form

A) 3 only
B) 1, 2, and 3 only
C) 2, 3 and 4 only
D) 1, 3, and 4 only