The Oracle Reference Architecture provides a specific definition of SOA Service. Which statement best describes the relationship between SOA Service and Web Service? 

A Web Service is one possible type of SOA Service. 

A SOA Service is a Web Service with a defined Service Contract. 

A SOA Service may be implemented using a Web Service Interface. 

All SOA Services are Web Services, but not all Web Services are SOA Services. 

All Web Services are SOA Services, but not all SOA Services are Web Services.