Industry conditions change because of:Select one:a$.$ changes in the barriers to entry and the degree of competition from substitute products.b$.$ appear when an industry begins to mature but are seldom present during early stages of the industry life cycle.c$.$ newly emerging industry threats and industry opportunities that alter the composition of the industry's strategic groups.d$.$ newly emerging industry key success factors.e$.$ important forces enticing or pressuring certain industry participants $($competitors$,$ customers, suppliers$)$ to alter their actions in important ways.