To determine the strongest base among the given options, we will analyze the ability of each base to donate electrons based on their hybridization and resonance structures.
### Step-by-Step Solution:
1. **Identify the Options**:
We need to analyze the structures of the bases provided in the options. Let's denote them as Option 1, Option 2, Option 3, and Option 4.
2. **Analyze Option 1**:
- The structure has a nitrogen atom that is sp² hybridized.
- In sp² hybridization, the lone pair of electrons is involved in resonance and is not easily available for donation.
- Due to this resonance and the acidic character of sp² hybridized nitrogen, it holds the lone pair more effectively.
- **Conclusion**: This option is not the strongest base.
**Hint**: Remember that sp² hybridized atoms tend to hold onto their lone pairs more tightly due to their involvement in resonance.
3. **Analyze Option 2**:
- This structure also has a nitrogen atom with its lone pair in conjugation with a ring.
- The lone pair participates in resonance, which reduces its availability for donation.
- **Conclusion**: This option is also not the strongest base.
**Hint**: Look for resonance structures; they can stabilize lone pairs and reduce basicity.
4. **Analyze Option 3**:
- The nitrogen in this structure is sp³ hybridized.
- In sp³ hybridization, the lone pair is not involved in resonance and is more available for donation.
- Therefore, this nitrogen can easily donate its lone pair, making it a stronger base compared to the previous options.
- **Conclusion**: This option is likely the strongest base so far.
**Hint**: Sp³ hybridized atoms generally have more available lone pairs for donation, increasing basicity.
5. **Analyze Option 4**:
- This structure is aniline, where the nitrogen lone pair is again in resonance with the aromatic ring.
- The resonance delocalizes the lone pair, making it less available for donation.
- **Conclusion**: This option is not the strongest base.
**Hint**: Again, check for resonance; it can significantly affect the availability of lone pairs.
6. **Final Comparison**:
- After analyzing all options, we find that Option 3, with the sp³ hybridized nitrogen, has the highest basicity.
- Options 1, 2, and 4 are less basic due to resonance effects and hybridization.
### Final Answer:
The strongest base among the given options is **Option 3**.
