To Ensure Delivery of the Proper Drug Dosage with a Metered

To ensure delivery of the proper drug dosage with a metered dose inhaler, which of the following must be done before its use?
1) The canister valve stem should be cleaned with a pin.
2) The canister should be warmed to hand or body temperature.
3) The canister should be vigorously shaken.

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