**Core Concept**
Toxoplasmosis, caused by the protozoan parasite *Toxoplasma gondii*, is a zoonotic infection that can affect various hosts, including humans. The dissemination of *T. gondii* from the mother to the fetus during pregnancy is a critical aspect of toxoplasmosis, leading to congenital toxoplasmosis.

**Why the Correct Answer is Right**
During pregnancy, *T. gondii* can cross the placenta and infect the fetus, leading to congenital toxoplasmosis. This occurs when the parasite is reactivated from a latent infection in the mother, allowing it to disseminate to the fetus. The parasite can evade the maternal immune system and infect the placenta, leading to fetal infection.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
The risk of congenital toxoplasmosis is highest when a pregnant woman is infected with *T. gondii* for the first time during pregnancy, especially during the first trimester. Pregnant women should avoid undercooked meat, cat feces, and contaminated soil to reduce the risk of toxoplasmosis.

**Correct Answer: B. Oocysts from cat feces.**