BCG vaccination is given to protect against tuberculosis (TB). The correct answer in this case is option 4, within 15 days. BCG vaccination is typically given to newborns within the first few days of life, usually before they leave the hospital. It is important to administer the BCG vaccine as early as possible to provide protection against TB. The vaccine is given as a single dose injection, usually on the upper left arm. Administering the BCG vaccine within the first few weeks of life helps to ensure that infants are protected against TB and reduce the risk of developing severe forms of the disease. It is important to follow the recommended vaccination schedule to ensure maximum effectiveness of the vaccine.