1)There are two major approaches to selling music online, where, once a song is recorded, it costs basically nothing to send it to someone. One is buying downloads, like on iTunes, where you pay $1 for each song. The other is streaming, like on Spotify, where you pay a single fixed price of $10 per month and get to listen to as much music as you like.

a.What is the marginal cost to iTunes or Spotify of allowing another person to listen to a digital download of a song that already exists?

answer as a number, round to the nearest dollar.