Which one of the following is an example of `3^(@)` amide ?

Options

A.
B.
C.
D.

Explanation

To determine which of the given options is an example of a 3° (tertiary) amide, we need to understand the structure of amides and how to classify them based on the number of hydrogen atoms attached to the nitrogen atom.

### Step-by-Step Solution:

1. **Understand the Structure of Amides**:
- An amide has the general structure R-CO-NH2, where R is a hydrocarbon group. The amide functional group consists of a carbonyl group (C=O) attached to a nitrogen atom (N).

2. **Identify the Degrees of Amides**:
- **1° Amide (Primary)**: The nitrogen is bonded to one carbon group and has two hydrogen atoms (e.g., R-CO-NH2).
- **2° Amide (Secondary)**: The nitrogen is bonded to two carbon groups and has one hydrogen atom (e.g., R-CO-NHR').
- **3° Amide (Tertiary)**: The nitrogen is bonded to three carbon groups and has no hydrogen atoms (e.g., R-CO-NR'R'').

3. **Analyze the Given Options**:
- Look at each option provided in the question and identify the number of hydrogen atoms attached to the nitrogen atom in each amide structure.
- The correct option will be the one where the nitrogen atom is bonded to three carbon groups and has no hydrogen atoms.

4. **Select the Correct Answer**:
- After analyzing the options, identify which one corresponds to the structure of a 3° amide, where nitrogen has no hydrogen atoms attached.

### Conclusion:
- The correct answer is the option where the nitrogen is bonded to three carbon groups (R-CO-NR'R'') and has no hydrogen atoms.