The correct option is A proximal convoluted tubule of nephron
The cuboidal epithelium is composed of a single layer of cube-like cells. This is commonly found in ducts of glands and tubular parts of nephrons in kidneys. Its main functions are
secretion and absorption.
Proximal convoluted tubule is a part of nephron that has a major role to play in reabsorption of essential nutrients, electrolytes (70-80%) and water. It also selectively secretes certain ions to maintain the pH and ionic balance of body fluids. The presence of cuboidal epithelium with brush border microvilli helps in increasing the surface area for reabsorption.
The eustachian tube is lined by pseudostratified columnar epithelium.
The intestine is lined by columnar epithelium.
The ducts of salivary gland are lined by compound epithelium.