The correct answer is D. All of the mentioned.
Load balancing virtualizes systems and resources by mapping a logical address to a physical address. This means that multiple instances of various Google applications can run on different hosts. However, Google does not use hardware virtualization. Instead, it uses software virtualization.
Software virtualization is a technique that allows multiple operating systems to run on a single physical machine. This is done by creating a virtual machine (VM) for each operating system. The VM is a software program that simulates a physical machine. It has its own CPU, memory, storage, and network interface.
Google uses software virtualization to run its applications on a large number of servers. This allows Google to scale its infrastructure up or down as needed. It also allows Google to run multiple versions of the same application on the same server. This is useful for testing new versions of applications before they are released to the public.
Hardware virtualization is a technique that allows multiple operating systems to run on a single physical machine by using the hardware resources of the machine directly. This is done by using a hypervisor, which is a software program that manages the virtual machines.
Google does not use hardware virtualization because it is not as efficient as software virtualization. Software virtualization is more efficient because it does not require the use of a hypervisor. Hypervisors can add overhead to the system, which can reduce performance.
In conclusion, the correct answer is D. All of the mentioned. Load balancing virtualizes systems and resources by mapping a logical address to a physical address. This means that multiple instances of various Google applications can run on different hosts. However, Google does not use hardware virtualization. Instead, it uses software virtualization.