BCD Co is a large trading company. Steve is the administration manager and is also responsible for legal and compliance functions. Sheila is responsible for after-sales service and has responsibility for ensuring that customers who have purchased goods from BCD Co are fully satisfied. Sunny deals with suppliers and negotiates on the price and quality of inventory. He is also responsible for identifying the most appropriate suppliers of plant and machinery for the factory. Sam is the information technology manager and is responsible for all information systems within the company. According to Porter's value chain, which of the managers is involved in a primary activity as opposed to a support activity?