Explanation
The Active and Configured CUIC Users for the 2K deployment model are 200 and 800 respectively. This means that the CUIC server can support up to 200 concurrent users and up to 800 configured users. A concurrent user is a user who is logged in to CUIC and actively using the application. A configured user is a user who has an account in CUIC, regardless of whether they are logged in or not. The 2K deployment model is one of the UCCE deployment types that defines the maximum number of agents, supervisors, and reporting users that can be supported by the system. The 2K deployment model can support up to 2000 agents, 200 supervisors, and 200 CUIC concurrent users12. References:
Cisco Unified Contact Center Enterprise Installation and Upgrade Guide, Release 12.5 (1) and 12.5 (2) - CLI Commands during Installation and Upgrade 2 Cisco 500-444 Quiz 1 Topic 8 Questions 1-5 1

The sync job that runs every 10 minutes to bring back the OUTOFSYNC machine to the IN_SYNC state is the Automated Differential sync job. This job compares the configuration files on the primary and secondary servers, copies the changes from the primary to the secondary, and then executes the configuration commands to bring the secondary server into the same state as the primary. The Manual Differential sync job is a similar process, but it requires user intervention to manually select the changes that need to be synchronized from the primary to the secondary server. The OnDemand sync job is a one-way process that pushes the configuration from the primary server to the secondary server, and the Push sync job is a one-way process that pushes the configuration from the secondary server to the primary server.

The URL for the VOS O/S admin page is https://<FQDN>:8443/osadmin. This page allows administrators to manage the VOS operating system, including viewing logs, managing users and groups, and managing system settings. It is also possible to access the VOS platform administration page from this page, as well as access the VOS REST API. Reference: https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/vos/admin/admin_reference/vos_admin_reference_chapter_01001.html

Explanation
UC on UCS Spec Based is a deployment option for Cisco Unified Communications (UC) applications on Cisco Unified Computing System (UCS) servers that allows customers to choose their own hardware configuration based on a set of rules and guidelines1. The two descriptions that apply to UC on UCS Spec Based are:
A: may be available as a packaged offer such as the Cisco Business Edition 7000 Platform. This is true because Cisco Business Edition 7000 (BE7000) is a packaged solution that includes a UCS server and preloaded UC applications that can be configured according to the customer's needs. The UCS server can be either a Tested Reference Configuration (TRC) or a Specs-based configuration, depending on the customer's preference and requirements2.
C: defined as Rule Based. This is true because UC on UCS Specs-based deployments follow a set of rules and guidelines that define the minimum and maximum hardware specifications, such as CPU, memory, disk, network, and power supply, that are required to support the UC applications. The rules and guidelines also specify the supported virtualization software versions, co-residency policies, and performance expectations1.
The other options are incorrect because:
B: VMware vCenter is required. This is false because VMware vCenter is not mandatory for UC on UCS Specs-based deployments, although it is recommended for managing multiple UCS servers and VMs. VMware vCenter is only required for certain UC applications, such as Cisco Unified Contact Center Enterprise (CCE) and Cisco Unified Intelligence Center (CUIC), or for certain features, such as VMware High Availability (HA) and VMware Distributed Resource Scheduler (DRS)13.
D: defined as Configuration Based. This is false because UC on UCS Specs-based deployments are not defined by a fixed hardware configuration, but rather by a range of hardware specifications that can be customized by the customer. Configuration Based is a term that applies to UC on UCS TRC deployments, which are predefined and validated hardware configurations that are supported by Cisco1.
E: VMware vSphere is optional. This is false because VMware vSphere is the only supported virtualization software for UC on UCS Specs-based deployments. VMware vSphere includes the VMware ESXi hypervisor and the VMware vCenter Server, which provide the virtualization platform and management tools for the UC applications. VMware vSphere is not optional, but rather mandatory for UC on UCS Specs-based deployments1.
References:
1: Cisco Collaboration Virtualization - Unified Communications in a Virtualized Environment 2: Cisco Business Edition 7000 Version 12.5 Ordering Guide 3: Cisco Collaboration Virtualization - VMware Requirements