In which of the following all electronic effects namely inductive, mesomeric and hyperconjugative effects are present?

Options

A.
B.
C.
D.

Answer

To determine which compound exhibits all three electronic effects—inductive, mesomeric, and hyperconjugative—we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Electronic Effects**:
- **Inductive Effect**: This is the permanent effect due to the electronegativity difference between atoms, leading to a shift of electron density along a chain of atoms.
- **Mesomeric Effect**: This refers to the delocalization of electrons through π-bonds or lone pairs, often seen in conjugated systems.
- **Hyperconjugative Effect**: This is the interaction of σ-bonds (typically C-H or C-C) with an adjacent empty p-orbital or π-bond, which stabilizes the molecule.

2. **Analyzing Option 1**:
- The compound in option 1 does not allow for the presence of all three effects. The shifting of π-bonds leads to an anti-aromatic system, which is unstable and does not exist. Hence, it cannot be the answer.

3. **Analyzing Option 2**:
- This compound has a –M (minus mesomeric) group due to the presence of a carbonyl (C=O) group, which contributes to resonance. It also has an inductive effect due to electronegative atoms. However, it lacks hyperconjugation, as there are no adjacent σ-bonds interacting with π-bonds. Thus, this option is not the answer.

4. **Analyzing Option 3**:
- Similar to option 2, this compound exhibits a –M effect due to the carbonyl group, and it shows inductive effects. However, it does not have hyperconjugation, as there are no suitable σ-bonds to contribute to this effect. Therefore, this option is also not the answer.

5. **Analyzing Option 4**:
- In this compound, there is a +I (positive inductive) effect due to the presence of alkyl groups (like CH₃). It also exhibits resonance due to the presence of π-bonds, contributing to the mesomeric effect. Additionally, the presence of adjacent C-H bonds allows for hyperconjugation. Therefore, this option contains all three electronic effects.

### Conclusion:
The correct answer is **Option 4**, as it is the only compound that exhibits inductive, mesomeric, and hyperconjugative effects.