**Core Concept**
Toxoplasmosis is a zoonotic infection caused by the protozoan parasite Toxoplasma gondii. The transmission of Toxoplasma can occur through various routes, and understanding these pathways is crucial for prevention and management.

**Why the Correct Answer is Right**
The correct transmission route of Toxoplasma involves the ingestion of oocysts shed by infected cats in contaminated soil or water. This occurs when humans accidentally ingest these oocysts while gardening, hiking, or engaging in other outdoor activities. The oocysts then undergo sporulation, allowing the parasite to infect the host's intestinal epithelial cells.

**Why Each Wrong Option is Incorrect**
**Option A:** Ingestion of tissue cysts from undercooked meat is a mode of transmission, but it's not the primary transmission route.
**Option B:** Vertical transmission from mother to fetus during pregnancy is a significant concern, but it's not the primary route of transmission in the general population.
**Option C:** Fecal-oral transmission from person-to-person is not a significant route of Toxoplasma transmission.

**Clinical Pearl / High-Yield Fact**
Toxoplasmosis can have serious implications for immunocompromised individuals, such as HIV/AIDS patients, and for pregnant women, who should avoid undercooked meat and cat feces to minimize the risk of vertical transmission.

**Correct Answer: A. Ingestion of oocysts from contaminated soil or water.**