Given the Following Frequency Distribution, How Many Pieces of Data

Multiple Choice

Given the following frequency distribution, how many pieces of data were less than 28.5? $$\begin{array} { | l | l | } \hline \text { Class Boundaries } & \text { Frequencies } \\\hline 13.5 - 18.5 & 4 \\\hline 18.5 - 23.5 & 9 \\\hline 23.5 - 28.5 & 12 \\\hline 28.5 - 33.5 & 15 \\\hline 33.5 - 38.5 & 17 \\\hline\end{array}$$

A) 12
B) 9
C) 25
D) 17