Which of the following is not an antibiotics ?

Options

A. Chloramphenicol
B. Ofloxacin
C. Penicillin
D. Phenelzine

Explanation

To determine which of the following is not an antibiotic, we can follow these steps:

### Step 1: Understand what antibiotics are
Antibiotics are a class of drugs that are used to treat bacterial infections. They work by killing bacteria or inhibiting their growth.

### Step 2: Identify examples of antibiotics
Some well-known antibiotics include:
- **Chloramphenicol**
- **Ofloxacin**
- **Penicillin**

### Step 3: Analyze the options given
We need to look at the options provided in the question and identify which one is not an antibiotic. The options include:
1. Chloramphenicol
2. Ofloxacin
3. Penicillin
4. Phenelzine

### Step 4: Classify the options
- **Chloramphenicol**: This is an antibiotic.
- **Ofloxacin**: This is also an antibiotic.
- **Penicillin**: This is another well-known antibiotic.
- **Phenelzine**: This is not an antibiotic; it is an antidepressant drug used to treat depression.

### Step 5: Conclusion
From the analysis, the option that is not an antibiotic is **Phenelzine**.

### Final Answer
The answer is **Phenelzine** (Option 4).

---