What can an infant's mother expect regarding her infant's protection from infections due to antibodies received during pregnancy?

An infant's immune system is indeed immature at birth, which makes them more susceptible to infections. While some antibodies are transferred from the mother through the placenta during pregnancy, they do not confer complete immunity. This passive immunity can help provide some level of protection against certain infections in the early months of life, but it is generally insufficient for long-term protection. The mother's antibodies will diminish over time, and the infant's own immune system takes time to develop fully and begin producing its own antibodies.

The other options suggest either an unrealistic complete protection from breastfeeding or mistakenly imply direct, long-lasting immunity from the transferred antibodies without acknowledging the limitations and risks associated with the infant’s developing immune defenses. In reality, ongoing protection through breastfeeding and vaccinations becomes essential as the infant grows.