Final answer:
The natural hazards associated with South Asia's tectonic activity are earthquakes and tsunamis. These occur due to active tectonic plate movements, capable of generating significant seismic and volcanic events.
Step-by-step explanation:
The natural hazards in South Asia that are associated with the region's tectonic activity are earthquakes and tsunamis. This is due to the active tectonic plate boundaries present in the area which not only cause significant earthquakes but also have the potential to trigger tsunamis, especially when these earthquakes occur underwater. For instance, the 2004 earthquake off the coast of Sumatra led to a devastating tsunami affecting multiple countries around the Indian Ocean. Similarly, volcanic activity in the Philippines, such as the 1991 eruption of Mount Pinatubo, is also driven by tectonic forces, although volcanic eruptions are not an option in the provided choices.
Other natural disasters such as hurricanes, tornadoes, flooding, landslides, desertification, and droughts, while severe, are not primarily caused by tectonic activity. Hurricanes and tornadoes arise out of meteorological conditions. Flooding and landslides can be secondary effects of earthquakes but can also result from heavy rainfall and human activities like deforestation. Desertification and droughts are usually results of climatic variations and human practices such as unsustainable agriculture rather than tectonic processes.