Gladiator Apparel is the market leader in the sportswear industry. Though most of its resources are common to those of its competitors, a few rare resources have helped the company gain and sustain a competitive advantage. Which of the following assets of Gladiator Apparel is most likely to be considered a rare resource that is contributing to its competitive advantage?a) The company's land and buildings
b) The company's plant and machinery
c) The company's raw material supplies
d) The company's design patents