Final answer:
The EMT should immediately administer the patient's EpiPen® as the best option for treating a pregnant patient in severe respiratory distress and with low blood pressure due to a bee sting anaphylaxis. Epinephrine found in the EpiPen® can counteract the drop in blood pressure and relax bronchial smooth muscle, providing immediate relief.
Step-by-step explanation:
Based on the information provided, the best option for the EMT is to immediately administer the patient's EpiPen®. Anaphylaxis is a severe allergic reaction that can be life-threatening, and the patient is already experiencing severe respiratory distress and low blood pressure. Epinephrine, which is found in the EpiPen®, can counteract the drop in blood pressure and relax bronchial smooth muscle, providing immediate relief to the patient. Medical control should also be contacted for further guidance, but administering the EpiPen® as soon as possible is crucial.