Final answer:
The part of the brain containing the pons, cerebellum, and medulla, which regulates basic human functions like breathing and heart rate, is known as the brainstem. The correct answer is C. Brainstem.
Step-by-step explanation:
The portion of the brain that includes the pons, cerebellum, and medulla, and is responsible for regulating basic human functions such as cardiovascular and respiratory systems, is known as the brainstem. The cerebellum, while attached to the brainstem, is considered a separate region and is integral in balance, coordination, and motor skills. The medulla oblongata, commonly referred to simply as the medulla, controls subconscious autonomic functions like breathing and heart rate. Therefore, the correct answer to the question is C. Brainstem.