Excretory organs of cockroach areA. TracheaB. KidneyC. NephridiaD. Malpighian tubules

The correct answer is:

D. Malpighian tubules

Explanation:

The excretory organs of a cockroach are the Malpighian tubules. These tubules are specialized structures that remove nitrogenous wastes from the hemolymph (the equivalent of blood in insects) and help in osmoregulation, maintaining the balance of salts and water within the insect's body.

Malpighian tubules work by absorbing waste materials, which are then transported into the digestive tract and eventually eliminated from the body along with feces. Other options listed are incorrect for the following reasons:

A. Trachea: This system is responsible for respiration in cockroaches, allowing gas exchange to occur.
B. Kidney: Kidneys are excretory organs found in vertebrates, not in insects.
C. Nephridia: Nephridia are excretory organs in annelids, such as earthworms, not in insects.
Thus, the correct answer is D. Malpighian tubules.