Final answer:
The first action a phlebotomy technician should take when a patient feels dizzy during a blood draw is to remove the tourniquet and needle to prevent further blood loss and minimize the risk of injury.
Step-by-step explanation:
When a patient reports feeling dizzy and light-headed during a blood draw, the phlebotomy technician should prioritize patient safety. The first and most immediate action to take would be B) Remove the tourniquet and needle. This action prevents further blood loss and potential harm. If the patient is at risk of fainting, placing the patient in a position that promotes blood flow to the brain, such as lying down or sitting with the head between the knees, may be considered immediately after ensuring the blood draw is safely terminated. Calling for help and instructing the patient to take deep breaths would follow accordingly to provide additional support and care.