The fire caused by the dry climate, which proved later the strongest one in the area, 　　　 quickly, and destroyed the forest.

A．to spread　　　 B．spreading 　 C．spread　　　 D．to have spread

The fire caused by the dry climate, which proved later the strongest one in the area,      quickly, and destroyed the forest.

A．to spread        B．spreading          C．spread         D．to have spread