Task: Question Answering
Input (English): Question: What transport system do thyroid follicular cells use to capture iodide through its basal pole ?: 
 Options:  <1> A primary active transporter. <2> An iodide exchanger with chloride. <3> A transporter called pendrina. <4> A process of pinocytosis. <5> A sodium iodide carrier.
Output (English): 5