$\text { Data Table A }$ -Refer to Data

$\text { Data Table A }$
$\begin{array}{|l|l|l|l|l|}\hline \begin{array}{c}\text { Sample } \\\text { Number }\end{array} & \text { Item 1 } & \text { Item 2 } & \text { /tem 3 } & \text { /tem 4 } \\\hline 1 & 13.10 & 13.90 & 12.80 & 13.20 \\\hline 2 & 13.80 & 13.00 & 12.50 & 12.70 \\\hline 3 & 14.00 & 12.90 & 13.10 & 13.50 \\\hline 4 & 12.30 & 13.30 & 12.80 & 13.60 \\\hline 5 & 13.10 & 12.60 & 13.30 & 12.90 \\\hline 6 & 12.50 & 13.40 & 12.80 & 13.30 \\\hline 7 & 13.60 & 12.70 & 13.30 & 13.80 \\\hline 8 & 12.50 & 13.50 & 13.10 & 12.90 \\\hline 9 & 13.00 & 13.60 & 12.70 & 13.20 \\\hline 10 & 12.80 & 12.90 & 12.70 & 13.30 \\\hline\end{array}$
-Refer to Data .The value 13.10 is ______.

A) the grand mean
B) the average of values for Item 1
C) the average of values for Item 2
D) the average of values for Item 3