Use the Following Information to Answer the Question $\begin{array}{l}H_{0}: \text { median }=0 \\H_{A}: \text { median } \neq 0\end{array}$

Use the following information to answer the question. Can deep-knee bends help you stay alert in class? Forty subjects were
measured for alertness at the beginning of class then voluntarily performed fifteen deep-knee bends followed by a forty
minute lecture. Each subject was then measured for alertness at the end of the lecture. The hypothesis test results for the sign
test are summarized below. Assume that all conditions for testing have been met: Hypothesis test results:
Parameter: Median of variable
$\begin{array}{l}H_{0}: \text { median }=0 \\H_{A}: \text { median } \neq 0\end{array}$
$\begin{array}{|l|l|l|l|l|l|l|l|}\hline \text { Variable } & \mathrm{n} & \mathrm{n} \text { for tests } & \text { Sample Median } & \text { Below } & \text { Equal } & \text { Above } & \text { P-value } \\\hline \text { Difference } & 40 & 35 & 1 & 14 & 5 & 21 & 0.4777 \\\hline\end{array}$
-What is the name and value of the test statistic?

A) $S=21$
B) $F=21$
C) $S=14$
D) $Z=5$