An alkaloid used as drug is

Options

A. Quinine
B. Reserpine
C. Atropine
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding Alkaloids**: Alkaloids are a class of naturally occurring organic compounds that mostly contain basic nitrogen atoms. They are known for their pharmacological effects and are often used in medicine.

2. **Identifying the Options**: The options provided are:
- Quinine
- Racerpine
- Atropine
- All of the above

3. **Analyzing Quinine**: Quinine is an alkaloid derived from the bark of the cinchona tree. It is primarily used to treat malaria, but it has also been studied for its potential effects on cancer treatment.

4. **Analyzing Racerpine**: Racerpine is another alkaloid that is used to manage high blood pressure. It works by affecting the central nervous system and has sedative properties.

5. **Analyzing Atropine**: Atropine is an alkaloid that is used in medicine to treat various conditions, including bradycardia (slow heart rate) and to reduce saliva production during surgery. It is also used in the treatment of certain types of poisoning.

6. **Conclusion**: Since all three compounds (quinine, racerpine, and atropine) are alkaloids and have medicinal uses, the correct answer to the question "An alkaloid used as a drug is" is "All of the above."

**Final Answer**: All of the above.

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