The Purkinje fibers are the specialized fibers found in:

Explanation

Option A is correct.The Purkinje fibers are the specialized fibers found in the human heart. Purkinje fibers are a network of specialized cardiac muscle fibers that conduct electrical impulses from the atrioventricular node (AV node) to the ventricles of the heart. They are responsible for coordinating the contraction of the ventricles, which allows them to pump blood efficiently. The Purkinje fibers are located in the subendocardial layer of the heart, which is the layer of muscle tissue that is closest to the endocardium, the inner lining of the heart. They are large, pale fibers that are easily distinguished from the surrounding cardiac muscle cells. The other options are not organs where Purkinje fibers are found: Lungs are the organs of respiration. They are responsible for exchanging oxygen and carbon dioxide between the body and the environment. The stomach is a digestive organ that is responsible for breaking down food into smaller molecules that can be absorbed by the body. The brain is the central nervous system organ that is responsible for controlling all of the body's functions.