The correct option is A The number of Bowman's capsules
Each nephron has a blind cup shaped structure called Bowman's capsule. Bowman's capsule encloses glomerulus and is a site of ultrafiltration. Therefore, the number of nephrons in kidney is equal to the number of Bowman's capsule. Malpighian body (renal corpuscle) is a collective term used for Bowman's capsule and its glomerulus.