Nicotine and cocaine are

Options

A. Peptides
B. Tannins
C. Alkaloids
D. Resin.

Answer

To answer the question "Nicotine and cocaine are," we will analyze the options provided and determine the correct classification for both substances.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are:
- Peptide
- Tannin
- Alkaloids
- Resins

2. **Understand the Nature of Nicotine and Cocaine**:
- **Nicotine**: It is a compound found in tobacco and is known for its stimulant effects.
- **Cocaine**: It is a powerful stimulant drug derived from the coca plant.

3. **Research the Classification of Compounds**:
- **Peptides**: These are short chains of amino acids and are not related to nicotine or cocaine.
- **Tannins**: These are polyphenolic compounds found in plants, often associated with astringency in foods and beverages, not related to nicotine or cocaine.
- **Alkaloids**: These are naturally occurring organic compounds that mostly contain basic nitrogen atoms. They are known for their pharmacological effects and include substances like nicotine, cocaine, caffeine, and morphine.
- **Resins**: These are sticky substances produced by plants, which do not include nicotine or cocaine.

4. **Conclusion**: Since both nicotine and cocaine are known to be alkaloids, we can confidently conclude that the correct answer is:
- **Option 3: Alkaloids**

### Final Answer:
Nicotine and cocaine are **alkaloids**.