Which of the following options best fits gap 15?

Directions: Read the passage and find the correct form of the missing word or phrase to complete it.

Music industry executives -----13---- recently expressed concern that the easy access to free digital recordings will dampen the willingness of customers to purchase music, but this concern is unwarranted. As recorded music became widely available in the form of LP’s and later cassette tapes and CDs, people ----------14------- to attend concerts and live music venues. Given that other recorded formats ---------15------- people to stop paying for musical entertainment, it is unlikely that the availability of digital recordings------16-------- customers to cease making  music purchases.