Answer: D) a report by the state traffic authority.
Step-by-step explanation: When writing an essay it is very important to support our arguments with evidence (facts, statistics, and examples) from reliable sources (sources that are objective and trustworthy). If we are writing an essay on the increase in drunk-driving accidents in our state, the most trustworthy source would be a report by the state traffic authority, because it won't include any opinions, just the facts and statistics.