The workload for this application normally stays at a certain baseline (Digital Leader)

Correct answer: C) Leverage sustained use discounts for your virtual machines.
Alternative C is the best option for controlling costs for several reasons:

1. Cost reduction:
Automatic discounts: Continuous use of VMs for more than 25% of the month guarantees progressive discounts, significantly reducing the total cost.
Flexibility: Different discount levels (1%, 5%, 10% and 30%) apply according to usage time, allowing you to optimize your costs according to your needs.

2. Ideal for predictable workloads:
Stability: The discount is applied automatically, without the need for manual management, ensuring predictability and stability in your costs.
Planning: You can plan ahead and make sure you're paying the lowest possible price for the VMs you use.

3. Suitable for the scenario described:
Consistent workload: The description of the workload indicates that it usually stays at a basic level, which makes it ideal for benefiting from the sustained use discounts.
Cost control: The main concern is to control costs, and sustained use discounts offer an effective way of doing this.

4. Additional advantages:
Simplicity: Easy to set up and manage, with no need for in-depth technical knowledge.
Transparency: Google Cloud Platform provides tools to monitor the use of VMs and view the discounts applied, giving you total control over your costs.
In summary, alternative C is the best choice for controlling costs due to its ability to significantly reduce VM costs, its simplicity of use and its suitability for predictable workloads such as the one described.