How can Helen provide free delivery for a small group of promotional products?

How can Helen provide free delivery for a small group of promotional products?

Set the default delivery for all products to a flat rate of £0.00
Add “Free delivery” to the Shopping campaign promotional text
Remove all delivery options from the Google Merchant Center account
Update the ‘delivery’ attribute to a fixed delivery price of £0.00 for only the promotional products

Answer is – Update the ‘delivery’ attribute to a fixed delivery price of £0.00 for only the promotional products