To meet the requirement of tracking shoe designs by products, a custom object for shoe designs should be created. This will allow for the designs to be associated with specific products, and for multiple designs to be created for one product across various stages.
Additionally, a custom lookup field should be configured for shoe designs on the Product object. This will enable the association between product and design and ensure that shoe designs cannot be deleted, as they will be linked to the product records.
Option A is incorrect because a master-detail relationship would not allow multiple designs to be associated with one product.
Option C is incorrect because there is no standard object for designs, so this option is not applicable.
Therefore, options B and D are the correct answers.