Answer:
d. improved technology of MP3 players.
Step-by-step explanation:
the CD players turned to have some inconvenients, as the CD itself had a shorter life , when people wanted to do sports while listening to music it was impossible to carry the CD while playing. The innovation in technology made possible to have a music player capable of being portable and yet overcoming important limitations present by the physical effects that rendered CD 's obsolete. The demand begin to arise as well as in the Internet a huge amount of content was to be distributed in the form of mp3 format, among others. that later contributed to people accumulating music anthologies and discographies. The first mp3 could easily replace several CD's as the capacity quickly began to increase and therefore people found it super convenient and conmfortable to carry many Artists in a single device.
Later further innovations that added value would be reflected in mp3s shifting to Ipods, and creation of online services like Itunes.