The correct option is A Glomerulus
Bowman's capsule is a cup-like sac of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. The mesonephros is one of three excretory organs that develop in vertebrates. Neurons are not part of the kidney. The nephridium (plural nephridia) is an invertebrate organ which occurs in pairs and performs a function similar to the vertebrate kidney. Thus, option A is correct.