Bidvest International Logistics (BIL), which provides an end-to-end supply-chain solution across a number of different industries, including essential services in the retail, healthcare and perishables sectors, noticed that some clients increased stock levels in preparation for future supply constraints, while volumes for clients providing non-essential services lessened during the Covid-19 pandemic. It is expected that the diversification of supply chains will result in multiple suppliers for the same products. Which one of the following is a purpose of the purchasing and supply function? Select one: a. Select suppliers b. Select product combinations c. Purchase material for personal consumption d. Control final price charged for products