Identify an antibiotic:

Options

A. sodium bicarbonate
B. streptomycin
C. alcohol
D. yeast

Explanation

**Step-by-Step Solution:**

1. **Understanding Antibiotics**: Antibiotics are chemical substances that are produced by microorganisms, such as bacteria and fungi. They are used to kill or inhibit the growth of other microorganisms, particularly pathogens that cause diseases.

2. **Identifying Options**: The question provides four options. We need to identify which one of these is an antibiotic. The options given are sodium bicarbonate, alcohol, yeast, and streptomycin.

3. **Analyzing Each Option**:
- **Sodium Bicarbonate**: This is a chemical compound commonly used as a baking soda. It does not have antibiotic properties.
- **Alcohol**: While alcohol can be used as a disinfectant, it is not classified as an antibiotic.
- **Yeast**: Yeast is a microorganism, but it is not pathogenic and does not function as an antibiotic.
- **Streptomycin**: This is an antibiotic that is effective against bacterial infections. It is derived from the bacterium *Streptomyces griseus* and is used to treat various infections, including tuberculosis.

4. **Conclusion**: Based on the analysis, the only option that qualifies as an antibiotic is **Streptomycin**.

**Final Answer**: The antibiotic is **Streptomycin**.

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