Taking into account the statement above: "In response to public concern about downtown parking availability, a city's mayor appoints a panel of traffic engineers, transportation officials and citizens to study the issue. Six months later, the panel published a 30-page report documenting its findings. Which factor will contribute to the credibility of the report as a source on the topic?
A. the length of the report
B. the cost of the report to the city
C. the number of tables and charts in the report
D. the qualifications of the contributors to the report"
The answer is: D.
Hope this helps.