For the Following Frequency Distribution of Quiz Scores, How Many $\begin{array}{cc}X & f \\\hline 5 & 6 \\4 & 5 \\3 & 5 \\2 & 3 \\1 & 2\end{array}$

Multiple Choice

For the following frequency distribution of quiz scores, how many individuals took the quiz?
$\begin{array}{cc}X & f \\\hline 5 & 6 \\4 & 5 \\3 & 5 \\2 & 3 \\1 & 2\end{array}$

A) $n=5$
B) $n=15$
C) $n=21$
D) cannot be determined