## Core Concept
The Expanded Programme on Immunization (EPI) was launched by the World Health Organization (WHO) to immunize children against six vaccine-preventable diseases. The EPI schedule includes vaccines against tuberculosis, diphtheria, pertussis, tetanus, poliomyelitis, and measles. The program aims to immunize children at specific ages to provide immunity against these diseases.

## Why the Correct Answer is Right
The EPI schedule primarily focuses on vaccines that are considered essential for global public health. The vaccines included in the EPI schedule are:
- BCG (Bacillus Calmette-Guérin) for tuberculosis
- DTP (diphtheria, tetanus, and pertussis)
- Poliovirus vaccine (oral or inactivated)
- Measles vaccine

## Why Each Wrong Option is Incorrect
- **Option A:** This option is not specified, but if it refers to a vaccine included in the EPI, then it would not be the correct answer.
- **Option B:** Similarly, without specifics, if it's part of EPI, it's incorrect as an "except" option.
- **Option C:** This option also lacks detail but would be incorrect if it's a vaccine within the EPI program.
- **Option D:** Hepatitis B vaccine, while crucial and often included in national immunization programs, was not part of the original EPI schedule but has been added by many countries.

## Clinical Pearl / High-Yield Fact
A key point to remember is that while the EPI originally targeted six diseases, many countries have expanded their programs. For example, the Hepatitis B vaccine is now commonly included in immunization schedules worldwide but was not part of the initial EPI focus.

## Correct Answer Line
**Correct Answer: D. Hepatitis B.**