The correct options are
B Main competitors of crops like weeds and threats like pests are destroyed.
D Provides nutrients that deposit on the soil in the form of ashes.
Burning provides suitable conditions to crops as their main competitors like weeds and threats like pests are destroyed. Burning also provides nutrients that deposit on the soil in the form of ashes. Burning typically results in the reduction of fuel and organic soil nutrient pool sizes, increases soil nutrient turnover rates, and redistributes nutrients through the soil profile.