Identify the Accurate Statement About Insulin Pens $\circ$ angle into Pinched Skin

Identify the accurate statement about insulin pens.

A) The pens increase accuracy in dose delivery.
B) Once a cartridge is loaded and opened, the loaded pen should be refrigerated.
C) The needle should be inserted at a 45 ^$\circ$ angle into pinched skin.
D) Insulin pens should be capped in order to avoid air being introduced in to the cartridge through the needle.