While all the options provided could offer useful information for evaluating wildfire risks, the data that would be most helpful to scientists specifically measuring those risks would be types of vegetation found in an area. Different types of vegetation will have varying flammability and fuel loads, which are critical factors in determining fire behavior and risk.
Drought conditions in an area is also significant, as dry conditions can lead to higher fire risks, but understanding the vegetation types provides insight into how those conditions might interact with potential fire fuel.