Which of the following statements is true about the industry life$-$cycle model?

a$.$

It is always accurate in predicting the stages of an industry.

b$.$

It is applicable only to industries that have gone through several shakeouts.

c$.$

It is not a useful way of thinking about and analyzing competition.

d$.$

It is a generalization that does not always follow a pattern in practice.

e$.$

It is a model that applies only to industries that have reached full maturity.