Final answer:
The size of the needle routinely used for venipuncture is typically 2.5-3 inches. Hence the correct option is C.
Step-by-step explanation:
Needle length is an important consideration in venipuncture to ensure that the needle is long enough to reach the vein for successful blood collection. The range of 2.5-3 inches is commonly used for venipuncture needles. However, it's important to note that specific needle sizes may vary based on factors such as the patient's age, size, and the location of the vein being accessed. Healthcare professionals choose the appropriate needle size based on these factors to optimize the procedure's effectiveness and minimize discomfort for the patient. Hence the correct option is C.