The molecule in which all atoms are not coplanar is

Options

A.
B.
C.
D.

Answer

To determine which molecule has all atoms that are not coplanar, we need to analyze the molecular structures provided in the question. Let's break down the steps to arrive at the correct answer.

### Step-by-Step Solution:

1. **Understand Coplanarity**:
- Coplanar atoms lie in the same plane, while non-coplanar atoms do not. We need to identify a molecule where at least one atom is not in the same plane as the others.

2. **Analyze the First Compound**:
- The first compound mentioned has two double bonds and a single hydrogen. Upon analysis, all the hydrogens and other atoms are found to be in the same plane.
- **Conclusion**: This compound is coplanar.

3. **Analyze the Second Compound**:
- The second compound also features two double bonds. However, there is a single carbon atom attached to two double bonds. The terminal hydrogens are not in the same plane as the other atoms due to the geometry of the molecule.
- **Conclusion**: This compound has non-coplanar atoms.

4. **Analyze the Third Compound**:
- The last compound is similar to the first one, where all atoms, including hydrogens, are arranged in the same plane.
- **Conclusion**: This compound is coplanar.

5. **Final Decision**:
- From the analysis, the second compound is the only one where all atoms are not coplanar. Therefore, the correct answer is option number C.

### Final Answer:
The molecule in which all atoms are not coplanar is **Option C**.