In the proximal tubule, _________ ions are pumped out of the tubule via ____________ transport. This creates an ____________ gradient, causing water to be reabsorbed through _______________.

• A. Potassium; active; osmotic; gaps between cells.
• B. Sodium; passive; osmotic; aquaporins.
• C. Potassium; active; ionic; gaps between cells.
• D. Sodium; active; osmotic; aquaporins.