**Core Concept:** Diphtheria is a bacterial infection caused by Corynebacterium diphtheriae, primarily affecting the respiratory tract. Diphtheria toxin produced by the bacterium causes tissue damage and inflammation, leading to the characteristic pseudomembrane formation. Antibiotics are not effective against the bacterium due to its extracellular location.

**Why the Correct Answer is Right:** In diphtheria carriers, the primary goal of treatment is to neutralize the diphtheria toxin and prevent its systemic spread. Antibodies against diphtheria toxin are essential for this purpose. Immune globulin (IG) contains high concentrations of preformed antibodies specific to diphtheria toxin, which can neutralize the toxin and prevent further damage to tissues and organs.

**Why Each Wrong Option is Incorrect:**

A. **Immunization (Vaccination)**: While vaccination is crucial for preventing diphtheria infection, it does not address the issue of toxin neutralization in carriers.

B. **Antibiotics**: Antibiotics target bacterial growth and are ineffective against diphtheria toxin. The toxin neutralization is the primary goal in carriers, not bacterial eradication.

C. **Anti-inflammatory agents**: These agents would not be effective in neutralizing diphtheria toxin or preventing tissue damage caused by the toxin.

D. **Observation and supportive care**: Treatment of diphtheria carriers involves active toxin neutralization, not just monitoring and providing supportive care.

**Clinical Pearl:** Treatment of diphtheria carriers is essential to prevent toxin release and systemic spread, which can lead to severe complications like myocarditis, encephalitis, and respiratory failure. Early initiation of immune globulin therapy can prevent toxin release and prevent severe complications in carriers.