Which of the following terrorist threats is considered to be a biological attack?

Which of the following terrorist threats is considered to be a biological attack? a. an explosion with intense light and heat, a damaging pressure wave, and a widespread radioactive material that can contaminate the air, water, and ground surfaces miles around the explosion site b. deliberate release of a toxic gas, liquid, or solid that can poison people and the environment c. deliberate release of germs or other biological substances into the air or water resulting in a wave of people seeking emergency medical attention for similar systems