In cloud computing, what is a hypervisor and which combination best describes its main purpose and the two major categories of hypervisors used in practice?

Introduction / Context:
Virtualization is a core building block of cloud computing because it allows many virtual machines to share the same physical hardware securely and efficiently. The component that makes this possible is called a hypervisor. When you understand what a hypervisor does and how it is categorized, you can better answer questions about Infrastructure as a Service, virtual machine provisioning, and performance differences between various cloud platforms.

Given Data / Assumptions:
We are discussing hypervisors in the context of server virtualization for cloud environments.The focus is on the definition and the two major types, not on specific vendor products.Type 1 and type 2 refer to how the hypervisor is installed relative to the hardware and host operating system.We assume basic familiarity with virtual machines and operating systems.

Concept / Approach:
A hypervisor, also called a virtual machine monitor, is a software layer that creates, runs, and manages virtual machines on a physical host. It allocates CPU, memory, storage, and network resources between guest operating systems. Type 1 hypervisors, also called bare metal hypervisors, run directly on the hardware and manage virtual machines without a general purpose host operating system. Type 2 hypervisors, also called hosted hypervisors, run on top of a conventional operating system, such as a desktop OS, and host virtual machines as applications. Cloud data centers commonly use type 1 hypervisors because they offer better performance and isolation.

Step-by-Step Solution:
Step 1: Identify the core function of a hypervisor, which is to manage and run multiple virtual machines on a single physical host.Step 2: Recall that type 1 bare metal hypervisors run directly on the hardware and are typically used in servers and cloud data centers.Step 3: Recall that type 2 hosted hypervisors run as applications on an existing operating system, which is common in development and testing environments.Step 4: Review the options and locate the one that correctly describes both the purpose and the two standard categories.Step 5: Confirm that option A matches this description precisely, while the others describe unrelated devices or mislabel the types.

Verification / Alternative check:
You can cross check the answer by recalling how major virtualization vendors classify their products. For example, server oriented hypervisors that run directly on hardware are promoted as bare metal or type 1, whereas desktop hypervisors that run on a host operating system are considered type 2. This matches the textbook classification which names hypervisors as type 1 bare metal and type 2 hosted. Since option A reflects this standard view, it is the correct choice.

Why Other Options Are Wrong:
Option B confuses hypervisors with network routers, which have a different function related to packet forwarding rather than virtual machine management. Option C treats a hypervisor as a backup tool, which is incorrect because backup software operates at a different layer. Option D suggests that a hypervisor is a browser plugin, which does not match any industry definition. Option E wrongly claims that a hypervisor is only a hardware chip for encryption, which again does not match the virtualization role described in cloud computing.

Common Pitfalls:
A frequent mistake is to believe that type 2 hypervisors are always used in the cloud, simply because many people first encounter virtualization on their desktop. In reality, large scale public and private clouds almost always rely on type 1 hypervisors for performance and isolation. Another pitfall is to mix up the roles of hypervisors and container runtimes. Containers share the host kernel and are not managed by hypervisors in the same way as full virtual machines. Clear separation of these concepts makes interview answers much stronger.

Final Answer:
The correct answer is: It is a virtualization layer that runs virtual machines, with type 1 bare metal and type 2 hosted hypervisors.