The correct answer is C. condition diagram.
A condition diagram is a type of diagram that shows the physical conditions of an accident location. It includes information such as the roadway limits, bridges, trees, and all details of roadway conditions. This information can be used to help investigators understand the cause of the accident and to prevent similar accidents from happening in the future.
A pie chart is a type of chart that shows the relative proportions of different parts of a whole. It is often used to show the distribution of data, such as the percentage of people who voted for different candidates in an election.
A spot map is a type of map that shows the location of specific points on a surface. It is often used to show the location of accidents, crime scenes, or other events.
A collision diagram is a type of diagram that shows the paths of two or more objects that collide. It is often used to analyze the cause of accidents.