This diagram depicts a nephron. Letter A is the beginning of the nephron, which is an enlarged sphere-shaped capsule that contains a mass of capillaries. A tube extends from the outer layer of the sphere, which travels in a convoluted way for a short distance. This tube then descends down and curves back along itself, forming a long loop. After finishing its ascent along the loop, the tube continues to travel in a convoluted way for a short distance until connecting to a darker-colored and wider tube that descends down and off of the page.
Based on the cross sections above, which of the following correctly matches the structure with its function?
