In a virtualized environment, this operating system runs on the physical machine.
a. guest
b. client
c. host
d. home

In a virtualized environment, host operating system runs on the physical machine.

Explanation:

Virtual environment is a computer which runs in a “virtual machine”. It is the hybrid of hardware platform and virtual machine environment. Placing multiple virtual machines on one physical server is called the host.

The advantage of setting virtual environment is that, it reduces “capital and operating costs”, increases productivity, simplified data center management, increases efficiency, Minimized “down time”, manage system easily.

A guest is not permanent and the access of the guest system changes as per the need of the guest.

Client is the machine which request or need the server to perform task.  

Home is not a valid environment name. So only the option C holds good.