How does transmission of HIV infection from an infected mother to her child occur?

Placenta

The correct answer is (b) Placenta.

Transmission of HIV infection from an infected mother to her child can occur during pregnancy, childbirth, or breastfeeding. The primary route of transmission is through the placenta, which is an organ that develops in the uterus during pregnancy and provides oxygen and nutrients to the fetus. The virus can cross the placenta and infect the developing fetus.

Option (a) Liver is incorrect. The transmission of HIV does not occur through the liver.

Option (c) Skin is incorrect. Direct transmission of HIV through intact skin is highly unlikely. HIV requires specific routes, such as direct contact with infected body fluids, to enter the body.

Option (d) All of these is incorrect. The transmission of HIV from an infected mother to her child does occur, and it commonly happens through the placenta.

Therefore, the most appropriate answer is (b) Placenta, as it represents the main route of transmission for HIV infection from an infected mother to her child.