The conditions for the combination of atomic orbitals to form molecular orbitals are stated below.
Mark the incorrect condition mentioned here.

Options

A. The combining atomic orbitals must have nearly same energy.
B. The combining atomic orbitals must overlap to maximum extent.
C. Combining atomic orbitals must have same symmetry about the molecular axis.
D. Pi `(pi)` molecular orbitals are symmetrical around the bond axis.

Explanation

To solve the question regarding the conditions for the combination of atomic orbitals to form molecular orbitals, we need to analyze each of the provided options and determine which one is incorrect.

### Step-by-Step Solution:

1. **Understanding the Conditions**:
We need to evaluate the conditions that allow atomic orbitals to combine and form molecular orbitals. The conditions generally include energy similarity, overlap extent, and symmetry.

2. **Evaluate Option 1**:
- **Statement**: "The combining atomic orbitals must have nearly the same energy."
- **Analysis**: This statement is correct. Atomic orbitals combine effectively when they have similar energy levels. For example, a 2p orbital will combine with another 2p orbital, but not with a 1s orbital due to significant energy differences.

3. **Evaluate Option 2**:
- **Statement**: "The combining atomic orbitals must overlap to maximum extent."
- **Analysis**: This statement is also correct. Greater overlap between atomic orbitals leads to a higher electron density between the nuclei, which is favorable for bond formation.

4. **Evaluate Option 3**:
- **Statement**: "Combining atomic orbitals must have the same symmetry about the molecular axis."
- **Analysis**: This statement is correct. For effective combination, atomic orbitals must have the same symmetry. For instance, a 2pz orbital can only combine with another 2pz orbital due to their orientation.

5. **Evaluate Option 4**:
- **Statement**: "Pi molecular orbitals are symmetrical around the bond axis."
- **Analysis**: This statement is incorrect. Pi molecular orbitals are actually non-symmetrical around the bond axis. In contrast, sigma molecular orbitals are symmetrical. For example, the 2p orbitals create lobes that are oriented above and below the bond axis, indicating non-symmetry.

6. **Conclusion**:
Based on the analysis, the incorrect condition is found in **Option 4**: "Pi molecular orbitals are symmetrical around the bond axis."

### Final Answer:
The incorrect condition is **Option 4**: "Pi molecular orbitals are symmetrical around the bond axis."