In which one of the following instances is rivalry among competing sellers notmore intense?

a. when certain competitors are dissatisfied with their market position and make moves to bolster their standing
b. when strong companies outside the industry acquire weak firms in the industry and launch aggressive moves to transform their newly-acquired competitors into stronger market contenders
c. when competitors are fairly equal in size and capability
d. when the products of rivals are weakly differentiated, buyer switching costs are low and market demand is growing slowly
e. when there are so many industry rivals that the impact of any one company's actions is spread thinly across all industrymembers