When preparing to give a child with insulin-dependent diabetes his dose of regular and NPH humulin insulin, which of the following actions would be most appropriate（）
A. Taking the premixed insulin out of the refrigerator, then withdrawing the amount into in one syringe.
B. Using two syringes, one for each type of insulin, and giving two injections.
C. Withdrawing the NPH insulin first, then withdrawing the regular insulin into one syringe.
D. Withdrawing the regular insulin first, then withdrawing the NPH insulin into one syringe.
力的是（）。