What Does the "Iodine Pump" Refer To

Multiple Choice

What does the "iodine pump" refer to?

A) a mechanism whereby target cells extract iodine-containing thyroid hormone from the blood
B) an active transport mechanism that concentrates iodine in the thyroid
C) a mechanism whereby T3 and T4 are released from thyroglobulin and pumped into the circulation
D) a protein-binding process whereby T3 and T4 are pumped throughout the body bound to plasma proteins