The drug that functions as depressant of CNS is

Options

A. Amphetamines
B. Caffeine
C. Opium
D. Cocaine

Answer

To determine which drug functions as a depressant of the central nervous system (CNS), we can analyze the options provided: amphetamines, caffeine, opium, and cocaine.

### Step-by-Step Solution:

1. **Understanding CNS Depressants**: CNS depressants are substances that reduce the activity of the brain and the nervous system. They can lead to relaxation, sedation, and a decrease in anxiety.

2. **Analyzing the Options**:
- **Amphetamines**: These are stimulants that increase brain activity and are not depressants.
- **Caffeine**: This is also a stimulant that increases alertness and does not function as a depressant.
- **Opium**: This is derived from the poppy plant (Papaver somniferum) and contains compounds known as opiates. Opiates have sedative effects and are known to depress CNS activity.
- **Cocaine**: This is a powerful stimulant that increases CNS activity and is not a depressant.

3. **Identifying the Correct Answer**: Based on the analysis, opium is the only drug listed that functions as a depressant of the CNS. It slows down respiratory activities, can cause sedation, and has various other effects on the body.

4. **Conclusion**: Therefore, the drug that functions as a depressant of the CNS is **opium**.

### Final Answer:
The drug that functions as a depressant of the CNS is **opium**.