Q:Of all nature's disasters, forest fires are often considered the most frightening. Moving at lightning speed, huge walls of flames can burn acres of land in just a few minutes. And although technology, including the use of tire-retardant chemicals, has greatly helped the fight against forest fires, they still take great damage. According to the National Interagency Fire Center, the fire season last year was the worst on record in terms of the number of fires and acres burned. There were 96.385 fires and9,873429 acres affected by fire in a year that was 125% more destructive than the 10-year average . These fires cost the federal govemment $1.5 billion to fight, and this figure does not include the money spent by local and state govemments as part of the effort. Fires in the southern states represented half of the national total last year. with Texas. Oklahoma and Arkansas being home to an usually high amount of activity. Wildfire have also taken place in Western states such as California, Colorado. and Alaska throughout the past 10 years. It is said that two-thirds of forest fires are started accidentally by people. almost one quarter are purposely set, while lighting causes 10%. Forest fires can have advantageous effects. Charcoal enriches soil, and some plant species grow well after. The cones of the jack pine tree, for example, will not spread their seeds unless there is heat. Douglas fir trees grow best in open sunlight areas after fire. Almost 25% forest fires are set _ . A) unexpectedly B) on purpose C) by lighting D) naturally
A:
B