Which of the following represents `3^(@)` amine :-

Options

A. `CH_(3)-CH_(2)-underset(NH_(2))underset(|)CH_(2)`
B. `CH_(3)-underset(NH_(3))underset(|)CH-CH_(3)`
C. `CH_(3)-underset(NH_(2))underset(|)overset(CH_(3))overset(|)C-CH_(3)`
D. `CH_(3)-underset(CH_(3))underset(|)N-CH_(3)`

Answer

To determine which of the given compounds represents a tertiary amine (3° amine), we need to understand the structure of amines and how they are classified.

### Step-by-Step Solution:

1. **Understand the Structure of Amines**:
- Amines are organic compounds that contain a functional group consisting of a nitrogen atom bonded to hydrogen atoms and/or alkyl groups. The general formula for an amine is R-NH2, R-NHR', or R3N, where R and R' are alkyl groups.

2. **Classify Amines**:
- **Primary Amine (1° amine)**: Contains one alkyl group attached to the nitrogen (R-NH2).
- **Secondary Amine (2° amine)**: Contains two alkyl groups attached to the nitrogen (R-NHR').
- **Tertiary Amine (3° amine)**: Contains three alkyl groups attached to the nitrogen (R3N).

3. **Analyze the Given Options**:
- We are looking for a compound that has three alkyl groups attached to the nitrogen atom.

4. **Identify the Correct Structure**:
- Among the options given, we need to identify which one has the structure of a tertiary amine. The correct structure for a tertiary amine will have the nitrogen atom bonded to three carbon-containing groups.

5. **Select the Correct Answer**:
- The fourth option is CH3N(CH3)2, which can also be written as CH3N(CH3)CH3. Here, nitrogen is bonded to three methyl groups (CH3), indicating that it is a tertiary amine. Therefore, the correct answer is option 4: CH3N(CH3)2.

### Final Answer:
The compound that represents a tertiary amine is **option 4: CH3N(CH3)2** (trimethylamine).