**Explanation:**

Antibiotics are medications that are used to treat bacterial infections. They work by killing or inhibiting the growth of bacteria. However, not all medications are antibiotics. Aspirin, which is the correct answer in this case, is not an antibiotic.

**Reasoning:**

To understand why aspirin is not an antibiotic, we need to clarify what aspirin is and how it works.

**1. What is Aspirin?**

Aspirin, also known as acetylsalicylic acid, is a nonsteroidal anti-inflammatory drug (NSAID). It is commonly used to relieve pain, reduce inflammation, and lower fever. Aspirin is widely available over-the-counter and is used for a variety of purposes, including relieving headaches, reducing pain and swelling, and preventing heart attacks and strokes in certain individuals.

**2. How Does Aspirin Work?**

Aspirin works by inhibiting the production of certain chemicals in the body called prostaglandins. Prostaglandins are involved in various processes, including inflammation, pain, and fever. By reducing the production of prostaglandins, aspirin can help alleviate pain and reduce inflammation.

**3. Difference Between Antibiotics and Aspirin:**

While antibiotics are specifically designed to target and kill bacteria, aspirin does not have any direct effect on bacteria. Aspirin primarily functions as an analgesic (pain reliever), antipyretic (fever reducer), and anti-inflammatory agent. It does not possess the ability to kill bacteria or inhibit their growth like antibiotics do.

**4. Antibiotics vs. Aspirin Usage**

Antibiotics are prescribed by healthcare professionals to treat bacterial infections, such as urinary tract infections, respiratory tract infections, and skin infections. On the other hand, aspirin is commonly used for conditions unrelated to bacterial infections, such as headaches, arthritis, and heart disease prevention.

In conclusion, while penicillin, ampicillin, and streptomycin are all examples of antibiotics used to treat bacterial infections, aspirin is not an antibiotic. Aspirin works as a pain reliever, fever reducer, and anti-inflammatory agent, but it does not possess the properties necessary to kill or inhibit the growth of bacteria.