What Does the Normal Protein That Is Encoded by the "Cystic

What does the normal protein that is encoded by the "cystic fibrosis" gene do?

A) transports chloride ions across membranes
B) delivers chloride ions to the endoplasmic reticulum
C) binds chloride ions to DNA prior to gene expression
D) binds chloride ions to bacteria so they are more easily recognized by white blood cells
E) the normal protein does more than one of these things