**Core Concept**
Household bleach, such as Chlorox, is a common disinfectant that contains a potent oxidizing agent. The active ingredient in bleach is a sodium salt of a strong acid, which is responsible for its antimicrobial properties.

**Why the Correct Answer is Right**
The correct answer is **sodium hypochlorite**. Sodium hypochlorite is a strong disinfectant that works by releasing hypochlorous acid, which is a potent antimicrobial agent. It disrupts the cell membranes of microorganisms, ultimately leading to their death. Sodium hypochlorite is effective against a wide range of bacteria, viruses, and fungi, making it a popular choice for household cleaning and disinfection.

**Why Each Wrong Option is Incorrect**
**Option A:** Ammonia is a common household cleaner, but it is not the active ingredient in bleach. Ammonia is a base that can be used to clean and deodorize surfaces, but it is not an oxidizing agent like sodium hypochlorite.

**Option B:** Hydrogen peroxide is another common household cleaning agent, but it is not the active ingredient in bleach. Hydrogen peroxide is an oxidizing agent, but it is less effective than sodium hypochlorite against a wide range of microorganisms.

**Option C:** No option was provided for option C.

**Clinical Pearl / High-Yield Fact**
When using bleach as a disinfectant, it's essential to dilute it according to the manufacturer's instructions to avoid skin and eye irritation. Additionally, bleach can be inactivated by organic matter, so it's crucial to clean surfaces thoroughly before applying bleach to ensure its effectiveness.

**Correct Answer:** B.