Answer:
B. Ecommerce is buying and selling of goods or services online; ebusiness includes ecommerce and all activities related to internal and external business operations.
Explanation:
E-commerce involves selling and buying activities online, involves placing orders and making payments. E-commerce can be business to business where businesses sell products to other businesses, or business to customer for example purchase of goods on Amazon. While e-business encompasses all business that is conducted online. It includes e-commerce and other activities like advertisement, email marketing, content management services, online job boards and so on.
So e-commerce is a subset of e-business.