Final answer:
Tuberculosis is a contraindication to breastfeeding due to the risk of infecting the infant. Small breast size, viral infections, or full-time employment are not contraindications. Sudden cessation of breastfeeding can cause breast engorgement and leakage.
Step-by-step explanation:
The condition that is a contraindication to breastfeeding among the options provided is tuberculosis (TB). If the mother has active, untreated TB, she should not breastfeed because of the risk of transmitting the infection to the infant. Breastfeeding is not contraindicated by small breast size, viral infections (with some exceptions, such as HIV, depending on the resources available), or full-time employment, as these do not inherently pose a risk of harm to the baby.
A person who stops breastfeeding suddenly might experience breast engorgement and leakage due to the continued production of milk that is not being expressed or consumed. The body continues to make milk if not signaled to stop by gradual weaning, leading to breast engorgement.