Single-celled eukaryotes are included in:

Options

A. Protista
B. Fungi
C. Archaea
D. Monera

Answer

### Step-by-Step Solution:

1. **Identify the Characteristics of Single-Celled Eukaryotes**:
- Single-celled eukaryotes are organisms that have a well-defined nucleus and membrane-bound organelles. This distinguishes them from prokaryotes, which do not have these features.

2. **Examine the Given Options**:
- **Option 1: Protista** - This kingdom includes single-celled eukaryotes.
- **Option 2: Fungi** - This kingdom primarily consists of multicellular organisms (though there are unicellular fungi like yeast, they are not classified as single-celled eukaryotes in the same context).
- **Option 3: Archaea** - This kingdom consists of prokaryotic organisms, which do not have a nucleus.
- **Option 4: Monera** - This kingdom also consists of prokaryotes, including bacteria.

3. **Determine the Correct Kingdom**:
- Since single-celled eukaryotes are defined by having a nucleus and organelles, the only suitable option is **Protista**. This kingdom is known for including various forms of single-celled organisms.

4. **Conclusion**:
- Therefore, the correct answer is **Option 1: Protista**.