Answer:
It is difficult to identify precisely in which stage of product life cycle each product is.
Explanation:
Products go through four stages in product life style starting from introduction, growth, maturity and decline.
It is difficult to identify in which stage a particular product is in as duration of each stage is unpredictable. This is the reason, David will not be able to precisely detect when maturity of a product ended and decline started.
A product cannot be just put in growth stage by merely checking its increasing sales record. Similarly, falling sales do not always imply decline.
Therefore, David needs to think fast for a good answer as it is impossible to accurately identify product life cycle.
