Photohome is a file hosting service that allows users to store up to $5$GB of data with no restrictions or charges. However, users have to pay a fee for advanced features on the cloud storage system and additional storage space. Which of the following business models does this best illustrate?

Question $9$ options:

A$)$

pay$-$as$-$you$-$go

B$)$

subscription$-$based

C$)$

freemium

D$)$

razor$-$razor$-$blade