A、An earthquake. B、A heavy storm. C、The eruption of a volcano. D、The seasonal wind. A

Last Sunday, huge waves moved across tile Indian Ocean and flooded coastal areas across southern and southeast Asia to East Africa. The waves were caused by one of the most powerful earthquakes ever recorded, measuring nine on the Richter Scale. The countries hardest hit were Indonesia, Sri Lanka, India and Thailand. More than 100,000 people are reported dead. Millions of people have been left homeless.