To solve this question, the user needs to have knowledge of cloud computing pricing models.
Now, let's go through each option and explain why it is right or wrong:
A. Free: This option is a pricing model for cloud computing. It's called the "Freemium" model, where the basic services are free, but additional features come with a cost.
B. Ladder: This option is not a cloud computing pricing model. Therefore, it is the correct answer to the question.
C. Pay per use: This option is a pricing model for cloud computing where users are charged based on the resources they consume.
D. Perpetual License: This option is not a cloud computing pricing model. It's a traditional software licensing model where users pay for software once and can use it indefinitely.