Final answer:
The most likely cause of severe shooting pains in the arm during a blood-draw from the basilic vein is that the vein has collapsed.
Step-by-step explanation:
The most likely cause of severe shooting pains in the arm during a blood-draw from the basilic vein is B. the vein has collapsed. When a vein collapses, it restricts the flow of blood and can cause pain. This can happen when the needle is inserted too deeply causing the vein to collapse against the surrounding tissue.
It is important for the healthcare professional to properly assess the vein and adjust the technique if the vein appears collapsed.