Final answer:
In a typical e-commerce platform, line_item.properties are not required, while title, image, and price are essential for product representation.
Step-by-step explanation:
The line item that would not be required within a typical e-commerce platform's product representation is b. line_item.properties. While title, image, and price are essential for identifying the product, displaying it to the user, and facilitating the purchase process, properties are extra attributes that may be the optional depending on the product type and the detail of information the seller wishes to the provide. For instance, line_item.properties might include size, color, or material, which are not always mandatory.