Michael Porter's Value Chain model categorises an organisation's activities into 'primary' and 'support' functions. Primary activities are those directly involved in the physical creation of the product, its marketing and delivery to buyers, and its support after sale. The options Logistics (both inbound and outbound), Operations (transforming inputs into the final product), and Marketing (including sales) are all core primary activities. These activities form the direct sequence of value creation for the customer. While all listed departments are part of the overall value chain, these three represent the primary, sequential flow.

D. Procurement: This is classified as a support activity in Porter's model. It underpins the entire value chain by sourcing inputs but is not part of the direct production flow.

E. Human Resources: This is a support activity that provides the personnel required for both primary and other support activities, rather than being a direct part of the value creation sequence.

1. Porter, M. E. (1985). Competitive Advantage: Creating and Sustaining Superior Performance. The Free Press. In Chapter 2, "The Value Chain and Competitive Advantage," Porter identifies the five generic categories of primary activities as Inbound Logistics, Operations, Outbound Logistics, Marketing and Sales, and Service (pp. 39-40).

2. Gamble, J. E., Peteraf, M. A., & Thompson, A. A. (2015). Essentials of Strategic Management: The Quest for Competitive Advantage (4th ed.). McGraw-Hill Education. Chapter 4, "Evaluating a Company’s Resources, Capabilities, and Competitiveness," presents a diagram and explanation of Porter's Value Chain, clearly distinguishing between primary activities (e.g., operations, logistics, marketing) and support activities (e.g., procurement, human resource management).

3. MIT Sloan School of Management. (2006). 15.902 Strategic Management I, Fall 2006. MIT OpenCourseWare. Lecture Notes, Session 5: Industry & Competitive Analysis. The course materials explicitly diagram the value chain, showing Operations, Logistics, and Marketing & Sales as primary activities, and Procurement and Human Resource Management as support activities.