Regarding Product Life Cycles,a Good Marketing Manager Knows That

Regarding product life cycles,a good marketing manager knows that

A) entirely different target markets may be involved at different stages.
B) a product that doesn't get beyond the introduction stage is still likely to be very profitable.
C) industry profits are increasing well after sales start to decline.
D) once a market goes into sales decline,oligopoly conditions set in.
E) All these answers are correct.