input field empty; do not select a label. Use each example only once.) chain of retail clothing stores Internet portal hotel chain \begin{tabular}{|l|l|l|} \hline \hline Gross profit by product line & Gross profit by product line & \multicolumn{1}{|l|}{} \\ \hline Sales returns as a percentage of sales & Sales returns as a percentage of sales & \\ \hline Inventory turnover by product line & Inventory turnover by product line & \\ \hline \end{tabular}