The correct option is B PCT
The first part of the nephron, just after the Bowman's capsule, is the proximal convoluted tubule. Brush border cells with multiple microvilli and a massive amount of mitochondria line this tube. This portion of the tubule is one of the largest contributors to electrolyte and water reabsorption. Around 65% of sodium and water and a little less chloride are filtered out of the plasma and are reabsorbed into the vasa recta in this section.