A. Business to Business (B2B)
B. Business to Customer (B2C)
C. Alpha-commerce (AC)
D. Consumer-to-business (C2B)

Solution

C. Alpha-commerce (AC)

Explanation

The categorization of types of e-commerce may vary depending on the perspective or classification used. However, one common classification of e-commerce includes the following main types:

• Business-to-Consumer (B2C) 
• Business-to-Business (B2B)
• Consumer-to-Consumer (C2C)
• Consumer-to-Business (C2B)