Streptococcus is a

Options

A. bacteria
B. virus
C. algae
D. fungi

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks to identify what "Streptococcus" is among the given options: bacteria, virus, algae, or fungal.

2. **Identifying Streptococcus**: Streptococcus is a type of microorganism. To classify it correctly, we need to gather information about its characteristics.

3. **Researching Streptococcus**: Upon researching, we find that Streptococcus is a genus of bacteria. Specifically, it is known to be spherical (cocci) in shape.

4. **Function of Streptococcus**: Streptococcus bacteria play various roles, including being involved in the fermentation process of certain foods, such as cheese.

5. **Choosing the Correct Option**: Since Streptococcus is identified as a type of bacteria, we can conclude that the correct answer to the question is option A: bacteria.

6. **Final Answer**: Therefore, the answer to the question "Streptococcus is a" is **bacteria**.