Choose the correct option to complete the statement according to the paragraph.
I was on my way home from a visit to my daughters in Texas when I heard on the radio that Hurricane Katrina was about to hit Mississippi and Louisiana. When I got home, I checked the Internet to get specific information. I learned that Hurricane Katrina would hit on Monday morning, August 29th, 2005. By Monday at 6.30 a.m., Hurricane Katrina hit. There was a terrible storm. All the phone lines went dead. Nearly 3,000 people, including me, had to go to the hospital because of injuries by Katrina on that day. The first floor of the hospital started flooding. The power went off. We couldn't drink the water because it was poisonous. All of a sudden, water came into the room through the windows. There were bad injuries as the windows were broken, and the furniture crashed into people. Outside the hospital was also terrible. All the power lines and trees were down. The trees blocked the highways. Nobody was able to pass the roads. Everybody was really terrified. I had to stay in hospital till the following Monday. It was the most terrifying week of my life.
The reason why they couldn't drink water after the hurricane was that ...... .