Answer: e. freemium approach
Explanation: As Iver Audio can be completely functional in its basic version, most users won't need to use the extra features. But for someone that will need them, the $19.99 upgrade will worth it because the extra features can be a lot useful. Furthermore, anyone using the "free" version can switch to the "premium" version after liking the program and its features. But of course, that decision it's up to the user.