What type of instances can you run on Google Compute Engine?

B is the correct answer because Google Compute Engine allows users to create custom virtual machine (VM) instances tailored to their specific needs. This means you can specify the number of CPUs, amount of memory, and various other resources to design a VM that fits your application's requirements. Additionally, you can choose the operating system and configure other settings, providing a high degree of flexibility and control over your computing environment.

The other options do not accurately capture the capabilities of Google Compute Engine. While pre-configured instances are available, users are not limited to just those; they can create instances from scratch with desired specifications. Additionally, the platform supports various operating systems beyond just Linux, including Windows, allowing for a wide range of applications and use cases. Lastly, the notion of restricted access contradicts the customizable nature of instances, as users have the ability to configure access and security settings according to their preferences. Thus, the ability to create custom virtual machine instances is a key feature that distinguishes Google Compute Engine.