**Core Concept**
Diphtheria, Pertussis, and Tetanus (DPT) vaccine is a combination vaccine that protects against three serious bacterial infections. The vaccine contains inactivated or whole-cell pertussis antigens, which can cause side effects, and diphtheria and tetanus toxoids. However, the pertussis component can be problematic in certain situations.

**Why the Correct Answer is Right**
The correct answer is related to the pertussis component of the DPT vaccine. The whole-cell pertussis vaccine can cause severe side effects, including fever, seizures, and even encephalopathy. In some cases, this has led to the development of aseptic meningitis or encephalitis. To mitigate this risk, the acellular pertussis vaccine was developed, which is safer but less effective.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not a contraindication for DPT vaccine. Allergic reactions to the vaccine are rare but can occur.
* **Option B:** This option is not a contraindication for DPT vaccine. Neurological disorders, such as cerebral palsy, are not directly related to the DPT vaccine.
* **Option C:** This option is not a contraindication for DPT vaccine. Pregnancy is not a contraindication, but caution is advised due to the potential for fetal exposure to the vaccine.

**Clinical Pearl / High-Yield Fact**
The DPT vaccine contains inactivated or whole-cell pertussis antigens, which can cause severe side effects, including fever, seizures, and encephalopathy. The acellular pertussis vaccine is a safer alternative but less effective.

**Correct Answer: B. Neurological disorders such as cerebral palsy.**