An interesting read I must say. Took me 10 minutes to read and do all four questions. Got them all correct.
1. Which of the following is mentioned in the passage as an advantage of the PLC marketing concept?
A. It encourages decision makers to nurture seemingly no-growth markets. --> Nope, A happens because of the lack of PLC (last part in the passage)
B. It breaks the product life cycle into four distinct stages. --> tricky one, but B only states the definition of the PLC. In case you argue that because PLC has four stages, I can use suitable strategy as long as I know which stage. In that case, E is so much better, as B only states the cause of the advantages.
C. It generates new marketing strategies by using an "if-then" approach. --> If anything, PLC is likely to generate an old strat, because the passage said if you know what stage you're in, you know what to do, implying merely applying textbook knowledge to circumstances.
D. It exploits the fact that marketing opportunities are constrained by controllable forces. --> so wrong on many levels. First, "exploit" is a strong word. Second, [... thus constraining managerial action within narrow limits.] implies that PLC constrains something else, rather that getting constrained.
E. It provides guidelines that are beneficial in some situations. Correct, [The PLC concept is an "if-then" strategic tool: if one can identify the stage, then one knows which strategy to use] The correct answer always paraphrases.