In which of the following molecule/ions are the inductive effect, resonance effect, and hyperconjugation all operating simultaneously?

Options

A. `(CH_(3))overset(+)C`
B. `(CH_(3))_(3)C-overset(+)CH_(2)`
C. `CH_(2)=CH-CH=O`
D. `CH_(3)CH=CH-CH=O`

Explanation

To determine which of the given molecules/ions exhibits the inductive effect, resonance effect, and hyperconjugation simultaneously, we will analyze each option step by step.

### Step 1: Analyze each compound

1. **Option A: C₃H₃⁺ (C₃H₃ cation)**
- **Inductive Effect:** The C₃H₃ cation has alkyl groups that exhibit a +I (inductive) effect.
- **Resonance Effect:** There is no resonance effect since there are no π bonds or lone pairs that can delocalize.
- **Hyperconjugation:** Hyperconjugation can occur due to the presence of adjacent C-H bonds.
- **Conclusion:** Only +I effect and hyperconjugation are present; no resonance effect. This option is not correct.

2. **Option B: C₃H₃C⁺ (C₃H₃C cation)**
- **Inductive Effect:** The C₃H₃ group exhibits a +I effect.
- **Resonance Effect:** There is no resonance effect since there are no π bonds or lone pairs for delocalization.
- **Hyperconjugation:** Hyperconjugation is present due to adjacent C-H bonds.
- **Conclusion:** Only +I effect and hyperconjugation are present; no resonance effect. This option is not correct.

3. **Option C: C₂H₄=CH-C(=O) (Alkenyl ketone)**
- **Inductive Effect:** The double bond and carbonyl group can exhibit resonance but not a significant inductive effect.
- **Resonance Effect:** There is a resonance effect due to the carbonyl group (C=O) which can stabilize the structure.
- **Hyperconjugation:** There is no hyperconjugation since there are no adjacent C-H bonds that can stabilize through hyperconjugation.
- **Conclusion:** Only resonance effect is present; no inductive or hyperconjugation effects. This option is not correct.

4. **Option D: C₃H₃-CH=CH-C(=O) (Alkenyl ketone with alkyl group)**
- **Inductive Effect:** The C₃H₃ group exhibits a +I effect on the adjacent carbon.
- **Resonance Effect:** The double bond and carbonyl group can participate in resonance, stabilizing the structure.
- **Hyperconjugation:** Hyperconjugation occurs due to the adjacent C-H bonds of the alkyl group.
- **Conclusion:** All three effects (inductive, resonance, and hyperconjugation) are present in this compound.

### Final Answer
The correct option is **D** (C₃H₃-CH=CH-C(=O)), as it exhibits the inductive effect, resonance effect, and hyperconjugation simultaneously.