What type should the Architect document this new service as?

A new dent is moving from their existing ecommerce platform to B2C Commerce. They have an existing service that connects to the Email Marketing System. The endpoint of the service can directly parse the data posted by the customer from the Storefront page for marketing materials subscriptions. it if required that the service implementation on the B2C Commerce site supports authentication and encoding.

What type should the Architect document this new service as?
A . HTTP
B. HTTP Form
C. Generic
D. SOAP

Answer: D