Correct Answer: C
Explanation:
A nephron is a unit of structure and function in a kidney. A kidney contains about a million nephrons, each approximately 3 cm. long.
A nephron is a long tubule differentiated into four regions having different anatomical features and physiological role: Bowman’s capsule, proximal convoluted tubule (PCT), loop of Henle, and distal convoluted tubule (DCT). The latter opens into one of the collecting ducts. Nephridia are the excretory organs of annelids.