A Professor of Statistics at Wayne State University in the US

A professor of statistics at Wayne State University in the US wants to determine whether the average starting salaries among graduates of the 15 universities in Michigan are equal. A sample of 25 recent graduates from each university is randomly taken. The appropriate critical value for the ANOVA test is obtained from the F-distribution with number so of degrees of freedom equal to: $\begin{array}{|l|l|}\hline \text { A. } & 15 \text { and } 25 . \\\hline \text { B. } & 14 \text { and } 360 . \\\hline \text { C. } & 360 \text { and } 14 . \\\hline \text { D. } & 25 \text { and } 15 . \\\hline\end{array}$