Change in Contribution Margin could be sold. The operating income by unit of product is as follows:

$\backslash$table$[[,\backslash$table$[[$Sun Sound$],[$Headphones$]],\backslash$table$[[$Ear Bling$],[$Headphones$]]],[$Sales price,$$40\mathrm{.}10,$$$62\mathrm{.}60$