Virtual Desktop Infrastructure (VDI) delivers a desktop operating system hosted on a centralized server and streams the graphical user interface (GUI) to endpoint devices such as thin clients, zero clients, or standard PCs. According to CompTIA Core 1 (220-1201) virtualization objectives, VDI allows users to access their desktop environments remotely while all processing and data remain on the server.
Option A accurately describes this model: a GUI streamed from a server to thin clients. This approach improves centralized management, enhances security, and simplifies endpoint hardware requirements.
Provisioning a sandbox is an example of test or development virtualization, not desktop virtualization. High- performance workstations with a local OS are physical desktops, not VDI. Launching a virtual machine server on a hypervisor describes server virtualization, not desktop delivery.
CompTIA highlights VDI as a common enterprise solution that separates the desktop environment from the physical device, enabling flexibility, scalability, and centralized control.
References:CompTIA A+ Core 1 (220-1201) Official Study Guide - Virtualization, VDI, and Cloud Concepts

An automatic document feeder (ADF) is designed to speed up scanning jobs that involve many pages by feeding sheets through the scanner automatically, one after another, without requiring the user to lift the lid and position each page manually. For a 300-page contract, the biggest time loss is the manual handling of every page on a flatbed. With an ADF-equipped scanner or multifunction printer, the user can load a stack of pages into the feeder tray and the device will process them continuously, greatly improving productivity and reducing user effort. This is a common CompTIA A+ Core 1 concept when comparing scanner hardware features and selecting the correct device for high-volume tasks.
A flatbed scanner (A) is typically slower for large documents because it requires manual placement of each page. Duplexing (B) can be helpful when scanning double-sided documents because it captures both sides automatically, but it does not address the "each page must be scanned individually" issue as effectively as an ADF does for high page counts. Orientation configuration (D) only changes how pages are rotated or aligned in the output file and does not increase scan throughput. Therefore, an ADF is the best choice to increase scanning speed for a large contract.

Software as a Service (SaaS) provides users access to fully managed applications hosted in the cloud.
CompTIA A+ explains that SaaS is subscription-based and typically billed monthly or annually, which aligns perfectly with the phrase "recurring fee." Business productivity applications-such as Microsoft 365, Google Workspace, Zoom, Slack, and Salesforce-are classic examples of SaaS offerings.
SaaS applications run entirely in the provider's cloud environment, eliminating the need for installation, maintenance, or management by the customer. This makes SaaS ideal for businesses that need reliable, scalable tools without maintaining their own infrastructure.
DaaS (Desktop as a Service) provides virtual desktops.
PaaS (Platform as a Service) offers a development framework for building applications.
IaaS (Infrastructure as a Service) provides virtual servers, storage, and networking-not end-user productivity apps.
Thus, SaaS is the correct and only model that matches the description of subscription-based access to productivity applications.

CompTIA A+ emphasizes virtualization as an ideal solution during system phase-out or transition periods.
The correct approach here is a P2V (physical-to-virtual) conversion and hosting the server in an Infrastructure as a Service (IaaS) environment. This removes the need for physical hardware while still keeping the application operational for its final year. IaaS provides full control over OS and applications, making it suitable for legacy systems that cannot be rewritten.
Colocation (Option A) still requires physical hardware. PaaS (Option C) is inappropriate because PaaS requires rewriting or replatforming the application. Shutting down the server after a backup (Option D) makes the application immediately unusable.
Thus, the best method is to convert to a virtual machine and host it on IaaS.

A hypervisor allows multiple operating systems to run simultaneously on a single physical host, making it the ideal solution for providing concurrent access to different test environments. Developers can use virtual machines (VMs) for testing and development.
From CompTIA A+ 220-1101 Official Study Guide, Objective 3.7 - Compare and contrast cloud computing concepts:
"A hypervisor is software that enables multiple operating systems to run on a single host as virtual machines.
This is commonly used in development and testing environments for flexibility and isolation." Verified Source:
CompTIA A+ Core 1 (220-1101) Official Study Guide, Chapter 3: Virtualization CompTIA Exam Objectives 220-1101, Domain 3.7