host.co.in offers a diverse selection of operating systems for unmanaged VPS hosting plans. This includes popular Linux distributions like CentOS, Ubuntu, and Debian. For customers who prefer Windows, the option of Windows Server 2019 is also available. During the order process, customers can choose their desired operating system, and even install a custom operating system if needed. However, it's crucial to note that compatibility may vary, so it is advisable to consult with the support team beforehand to ensure a seamless selection process.