Which use case does NOT require the use of multiple sites or multiple instances?

When working with the agent REST APIs, the site context is important. What are two ways the site context can be set? (Choose two.)

A developer would like to pass two custom properties called interestRate and remainingPayments from the custom payment integration service to Commerce Cloud in the JSON response payload. The remainingPayments property should be returned to the storefront to be used in a custom widget.
Which code snippet included in the JSON response accomplishes this?

An organization has implemented loyalty points as a payment currency by creating a payment gateway extension with loyaltyPoints as one of the paymentMethodTypes and configuring the Custom Curency Payment webhook.
What additional step does the organization need to do to add loyalty points as a payment option on the Payments Method widget?

The Profile Navigation - Account Shoppers widget instance settings specifies the storefront role of buyer for the Account Address Book.

Note that the storefront role for the /accountaddressbook URL is specified as buyer.
Which configuration step is needed to allow a delegated administrator the privilege to create, edit, and delete account addresses?