Motor, Inc., a domestic C$-$Corporation, produces industrial engines at its U$.$S$.$ plant for sale in the United States and Canada. Motor, Inc. also has a plant in Canada that performs the final stages of production with respect to the engines sold in Canada. All the output of the Canadian plant is sold in Canada, whereas only $25\%$ of the output of the U$.$S$.$ plant is shipped to and sold in Canada. The other $75\%$ of the output of the U$.$S$.$ plant is sold to customers in the United States. The Canadian operation is treated as a branch for U$.$S$.$ tax purposes. During the current year, Motor, Inc.$$s total sales to Canadian customers were $$10,000,000,$ and the related cost of goods sold is $$7,000,000.$ The average value of production assets is $$30,000,000$ at the U$.$S$.$ plant and $$5,000,000$ at the Canadian plant.

a$.$ How much of Motor, Inc.$$s export gross profit of $$3,000,000($export sales of $$10,000,000$ less $$7,000,000$ cost of goods sold$)$ is classified as foreign$-$source income for U$.$S$.$ tax purposes?

b$.$ Now assume that the facts are the same as in part $($a$),$ except that the Canadian factory is structured as a wholly$-$owned Canadian subsidiary, rather than a branch. Motor, Inc.$$s sales of semi$-$finished engines to the Canadian subsidiary $($which still represent $25\%$ of its output$)$ were $$6,000,000$ during the year and the related cost of goods sold was $$4,000,000.$ The Canadian subsidiary$$s total sales of finished engines to Canadian customers $($which represents all its output$)$ was $$10,000,000$ and the related cost of goods sold is $$7,000,000.$ The average value of production assets is still $$30,000,000$ at the U$.$S$.$ plant and $$5,000,000$ at the Canadian plant. How much of Motor, Inc.$$s export gross profit of $$2,000,000$ is classified as foreign$-$source income for U$.$S$.$ tax purposes?