What caused the damage in the author&rsquos house?

Question

Read the following passage carefully and choose the most appropriate answer to the question out of the four alternatives. When I walked through what used to be my house after school that day, I was shocked to see how much damage there was. Whatever hadn’t burned was destroyed by the water and chemicals they had used to put out the fire. The only material things not destroyed were the photo albums, documents and some other personal items that my mother had managed to heroically rescue. But my cat was gone and my heart ached for her. There was no time to grieve. My mother rushed me out of the house. We would have to find a place to live, and I would have to go buy some clothes for school. We had to borrow money from my grandparents because there were no credit cards, cash or even any identification to be able to withdraw money from the bank. Everything had gone up in smoke.