Answer:
C. Volcanically derived carbon dioxide gas bubbled from the lake and suffocated people and animals nearby.
Step-by-step explanation:
On August 21, 1986, one of the strangest and most mysterious natural disasters in history occurred at Lake Nyos, formed on top of a volcanic crater in northwestern Cameroon.
Unexpectedly, the lake released thousands of tons of toxic carbon dioxide. The lethal cloud silently spread across the field at nearly 100 km / h, suffocating approximately 1,746 people and more than 3,500 head of cattle in a few minutes.
Many people in the villages of Cha, Nyos and Subum were silently asphyxiated in their sleep. Some were found with blood around their noses and mouths. When the few survivors woke up, they found no disturbance, no violence, only dead bodies. Even the flies dropped dead.