Many Fast-Food Restaurants,including Burger King,McDonald's,and Wendy's,no Longer Use Polystyrene Containers

Many fast-food restaurants,including Burger King,McDonald's,and Wendy's,no longer use polystyrene containers (which do not degrade as quickly as paper in a landfill) for packaging their products.Rather,these firms wrap their burgers in recycled paper wrappers,containers,and bags,usually clearly marked as such.These fast-food restaurants are practicing

A) triple-top line marketing.
B) green marketing.
C) consumerism.
D) an ecological code of ethics.
E) cause marketing.