The nurse has to administer Humulin R 18 units and NPH 35 units subcutaneously, daily at 7:30 AM. What is the correct order for drawing up these medications?
1- Inject into the Humulin R vial 18 units of air.
2- Inject into the NPH vial 35 units of air.
3- Withdraw 18 units of Humulin R insulin.
4- Withdraw 35 units of NPH insulin.
a) 2, 1, 4, 3
b) 1, 2, 4, 3
c) 1, 2, 3, 4
d) 2, 1, 3, 4