Find the Median for the Given Sample Data $\begin{array} { l l l l } 28 & 30 & 28 & 31 \end{array}$

Find the median for the given sample data.
-The number of vehicles passing through a bank drive-up line during each 15-minute period was recorded. The results are shown below. $\begin{array} { l l l l } 28 & 30 & 28 & 31 \end{array}$
$\begin{array} { l l l l } 31 & 28 & 33 & 30 \end{array}$
$\begin{array} { l l l l } 38 & 34 & 34 & 32 \end{array}$
$\begin{array}{llll}27 & 34 & 28 & 23\end{array}$
$\begin{array}{llll}18 & 30 & 30 & 30\end{array}$

A) 31 vehicles
B) 34 vehicles
C) 30 vehicles
D) 29.85 vehicles