Answer:
a. a phase-out
Step-by-step explanation:
Based on the information provided within the question in regards to the situation it seems that this is an example of a phase-out. This term refers to when a company abandons a plan or product little by little until it dies out. Which is what the company's in this situation are doing with the CD players since they realize that the technology is obsolete, no one will buy more, and making new ones or adding changes is a waste of time, money and resources.