One of the following durgs depresses (switch off) the activities of Nervous System and is known as sedative. It gives feeling of calmness, relaxation, or drrowsines. It is

Options

A. Opium
B. Heroin
C. Cocaine
D. Barbiturate

Answer

To solve the question regarding which drug depresses the activities of the nervous system and is known as a sedative, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for a drug that depresses the nervous system and induces feelings of calmness, relaxation, or drowsiness. This indicates we are looking for a sedative.

2. **Define Sedatives**: Sedatives are substances that reduce irritability or excitement. They work by depressing the central nervous system (CNS), leading to a calming effect.

3. **Analyze the Options**: The question likely provides multiple options to choose from. We need to evaluate each option based on their effects on the nervous system.

4. **Evaluate Each Drug**:
- **Opium**: Derived from the opium poppy, it has analgesic properties and is classified as a narcotic. It does not primarily induce calmness or drowsiness, so it is not the correct answer.
- **Heroin**: A derivative of morphine, it is known for its euphoric effects but does not primarily induce drowsiness or calmness. Thus, it is also incorrect.
- **Cocaine**: This is a stimulant that increases brain activity and does not provide relaxation or calmness. Therefore, it is not the correct choice.
- **Barbiturates**: These drugs are known to depress the CNS, leading to sedation, calmness, relaxation, and drowsiness. This aligns with the requirements of the question.

5. **Conclusion**: Based on the evaluation, the drug that fits the criteria of depressing the nervous system and providing feelings of calmness, relaxation, or drowsiness is **Barbiturates**.

### Final Answer:
The correct answer is **Barbiturates**.

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