**Core Concept**
Breastfeeding is a vital component of maternal-infant bonding and has numerous health benefits for both the mother and the infant. However, there are certain situations where breastfeeding may need to be modified or avoided due to the presence of infectious diseases or other medical conditions.

**Why the Correct Answer is Right**
Hepatitis B infection in the mother is not a contraindication for breastfeeding. This is because hepatitis B virus (HBV) is not transmitted through breast milk. The primary mode of HBV transmission is through perinatal exposure to the virus during delivery. Therefore, breastfeeding does not pose a risk to the infant, and it is recommended to continue breastfeeding even in the presence of hepatitis B infection in the mother. This is in contrast to other infectious diseases like HIV, where breastfeeding is contraindicated due to the risk of mother-to-child transmission.

**Why Each Wrong Option is Incorrect**
**Option A:** Active infection of herpes on the breast is a contraindication for breastfeeding. Herpes simplex virus (HSV) can be transmitted through breast milk, and breastfeeding can exacerbate the infection, leading to prolonged maternal illness and potential infant infection.

**Option C:** Mother has tuberculosis. Breastfeeding is generally contraindicated in cases of active tuberculosis (TB) due to the risk of transmitting the bacteria to the infant through breast milk. However, if the mother is on effective antitubercular therapy, breastfeeding may be continued while taking precautions to prevent transmission.

**Option D:** Mother is on chemoprophylaxis for leukemia. Chemoprophylaxis for leukemia involves the use of medications to prevent the development of leukemia. However, breastfeeding is contraindicated in cases where the mother is on certain medications, such as certain chemotherapeutic agents, that can be transmitted through breast milk and cause harm to the infant.

**Clinical Pearl / High-Yield Fact**
It is essential to note that breastfeeding is not contraindicated in all cases of maternal infection. Each situation should be assessed on a case-by-case basis, taking into account the specific infectious agent, the mother's treatment status, and the benefits and risks of breastfeeding for both the mother and the infant.

✓ Correct Answer: B. Mother has hepatitis B infection