Read the passage, and then answer the question. A team of scientists studied the sediment at the bottom of an ancient lake. They were able to determine the weather conditions of the Indus valley in ancient times. They found that the entire area had suffered a drought after the monsoons declined. This drought lasted 200 years. Because of the drought, there wasn’t enough food or water. The people of the Indus valley were forced to leave their cities.

What theory about the cause of the decline of the Indus civilization does the passage support?

A.
climate change
B.
invasion by an outside force
C.
rivers changing course
D.
spread of introduced diseases