In a value chain analysis:

Select one:

$$ A$.$ The links of the chain are the various entities beginning with the producers of raw materials and ending with the final customer

$$ B$.$ Processes are collections of related activities intended to achieve a common purpose, such as procurement or production

$$ C$.$ Activities are the units of work that take place within the various processes, such as moving products from one work station to another

$$ D$.$ All of the answers are correct