A. A type of extension running on a separate framework that provides specialized backend functionality and connects with SAP through RESTful Web services

B. A type of extension that allows you to extend SAP Commerce accelerator functionality, such as sharing on a social network

C. A commerce extension that provides optional functionality, such as behavioral targeting, vouchers, Solr faceted search, or subscriptions

D. A set of Java libraries, distributed as a JAR file, used to call external service providers, such as payment, tax, or fraud service providers.