yeah, that's why I started off saying:
if you are not using any product options
Since you are using options, how do you want to handle the option?
Will the options be updatable?
if you want the option to be updatable, the pass the option as a quersyring variable too:
go to the bindings panel and click the plus button, select URL Variable an name it "option"
then in design view for the cart display, select the option column and insert an eCart editable Select list. Insert -> Webassist -> eCart -> Updatable List
in the property inspector for the list, click the dynamic button, set the static values for the list of available options, then click the lightning bolt next to Select Value Equal to and select the option querystring variable.