This type of activity is an early example of A. ecosystem management.
To me, setting fire in this case sounds like a good idea, because it leads to all of these good things such as foraging space for deer, etc. Since it is a good thing, B and D are definitely incorrect because destruction and degradation are negative things. I'd say that C is also incorrect because you're not exploiting anything yet - you are just giving way for nature to take its course after you've pushed it a bit.
