To integrate a new form into the existing Cart.js controller, it's essential to ensure that the form definition and the controller are correctly linked via the form’s action attribute and the respective handler in the controller.

Option A:

Add an <action /> node to the form definition XML with the attribute formid="addRewardPass": This step correctly defines the action associated with the form, specifying which form it is (addRewardPass) and links it to the corresponding handler in the controller.

Add the key addRewardPass, with a processing function as a value, to the object passed to the Form.handleAction() method in the Cart.js controller: This ensures that when the form is submitted, the specific key (addRewardPass) directs the controller to handle the form submission using the designated processing function.

This option fully addresses the need to incorporate the form functionality into the existing Cart.js structure, ensuring that the form's submission triggers the appropriate processing logic.