In the given structure of the human brain below :
Cerebral cortex, thalamus, limbic system , corpora quadrigemina , hypothalamus, brain stem, cerebral aqueduct, cerebellar hemisphere.
How many structures are associated with the forebrain of human ?

Options

A. Three
B. Four
C. Five
D. Six

Answer

To determine how many structures are associated with the forebrain of the human brain from the given list, we will analyze each structure mentioned:

1. **Cerebral Cortex**: This is a part of the forebrain. It is responsible for various higher brain functions, including attention, perception, memory, and language coordination.

2. **Thalamus**: This structure is also part of the forebrain. It acts as a relay station for sensory and motor signals to the cerebral cortex.

3. **Limbic System**: This is a complex set of structures within the forebrain that is involved in emotions, behavior, and memory.

4. **Hypothalamus**: This is another component of the forebrain. It regulates various bodily functions, including temperature control, hunger, and the sleep-wake cycle.

5. **Corpora Quadrigemina**: This structure is not part of the forebrain; it is located in the midbrain and is involved in visual and auditory reflexes.

6. **Brain Stem**: This is also not part of the forebrain. It connects the cerebrum to the spinal cord and controls basic life functions.

7. **Cerebral Aqueduct**: This structure is part of the midbrain and connects the third and fourth ventricles, thus not part of the forebrain.

8. **Cerebellar Hemisphere**: This is part of the cerebellum, which is located behind the brainstem and is not part of the forebrain.

Now, compiling the structures that are part of the forebrain:
- Cerebral Cortex
- Thalamus
- Limbic System
- Hypothalamus

Thus, there are **4 structures associated with the forebrain**.

### Final Answer:
**4 structures are associated with the forebrain of the human brain.**