Which of the following statements is the most plausible explanation of the difference in observed net operating profit margins?

Widget Co$.$ and Tools Inc. both operate in the same industry. They are capital$-$intensive companies producing widgets. Below are selected data:

Widget Co$.$ Tools Inc.

Net operating assets$/$common equity

$\backslash$table$[[1\mathrm{.}37,1\mathrm{.}53],[19\%,21\%$