Let's break down the passage. In the first paragraph, we are told that in the last half-century, firefighters in North America have developed a powerful system for fighting wildfires using modern technology (1-3). However, too much firefighting is actually more detrimental than no firefighting at all (3-6). Then the importance of sporadic small fires is discussed in lines 9-19.
The second paragraph discusses the issues with disallowing small fires, e.g. "if fires are kept out of forests, however, deadwood and other fuels build up; then, when fire is sparked by lightning or some other cause, what results is a fire so large that it leaves total devastation."
The last paragraph is a suggestion of a new policy: "Land managers should therefore focus their efforts on fuel. A new kind of wildfire management that is designed to simulate the natural role of fire through a combination of selective harvesting and prescribed fires is the most promising method for controlling fuel."
Thus, answer choice (D): "recommends a fundamental policy change in light of evidence that current policy has created undesirable conditions," is correct. As outlined above, the entire passage is poised to suggest the new policy of fire-suppression due to the current firefighting policy being too effective and not allowing for small fires to burn up the fuel build up in forests.
Hope that clears things up! Please let us know if you have any other questions.
