This part of the human brain is also known as the emotional brain

The correct option is Limbic system.

Explanation:
The limbic system is a complex set of structures located on both sides of the thalamus, immediately beneath the cerebrum. It includes the hypothalamus, the hippocampus, the amygdala, and several other nearby areas. It is primary responsible for our emotional life, which is why it is widely known and referred to as the "emotional brain." It plays a major role in controlling behaviors necessary for self-preservation and survival, such as fight-or-flight responses, feeding, reproduction, and caring for our offspring.

Let's look at why the other options are incorrect:
- Epithalamus: This is a posterior segment of the diencephalon that primarily functions as a connection between the limbic system and other parts of the brain. It includes the pineal gland, which secretes melatonin and regulates circadian rhythms, rather than being the emotional brain itself.
- Broca's area: Located in the frontal lobe of the dominant hemisphere (usually the left), this region is critically involved in speech production and language processing, not emotional regulation.
- Corpus callosum: This is a large, C-shaped nerve fiber bundle found beneath the cerebral cortex. It acts as the primary communication bridge, connecting the left and right cerebral hemispheres, permitting data transmission between them.