Explanation
A vGPU profile is a configuration option that defines the amount of video RAM (vRAM) and other resources that are allocated to a virtual machine (VM) that uses a virtual graphics processing unit (vGPU). A vGPU profile can affect the rendering performance of a VM, as it determines how much graphics memory and processing power are available for displaying complex graphics content. Selecting vGPU profiles with higher video RAM can most likely solve the issue of poor rendering performance when trying to display 3-D content on virtual desktops, especially at peak times, as it can provide more graphics resources and improve the quality and speed of rendering. References: CompTIA Cloud+ Certification Exam Objectives, page 11, section 1.6

Moving the virtual machine to flash storage and testing again is what the administrator should do next to resolve the issue of disk-related performance issue with a virtual database server that has been identified as being caused by a lack of IOPS on the existing spinning disk storage. IOPS (Input/Output Operations Per Second) is a measure of how fast a storage device can read and write data. IOPS can affect performance of a virtual database server by determining how quickly it can access and process data from storage. Spinning disk storage is a type of storage device that uses rotating magnetic disks to store data. Spinning disk storage has lower IOPS than flash storage, which is a type of storage device that uses solid-state memory chips to store data. Flash storage has higher IOPS than spinning disk storage, which means that it can read and write data faster and more efficiently than spinning disk storage. Moving the virtual machine to flash storage and testing again can help to resolve the issue by increasing the IOPS and improving the performance of the virtual database server.

Explanation
The correct answer is C. Anti-affinity rule.
An anti-affinity rule is a configuration option that prevents two or more virtual machines (VMs) from running on the same physical host. This can improve the availability and fault tolerance of the VMs, as it reduces the risk of losing multiple VMs due to a single host failure. An anti-affinity rule can also improve the performance and load balancing of the VMs, as it distributes the workload across different hosts and avoids resource contention .
A round-robin method is a load balancing algorithm that distributes incoming requests to a pool of servers in a circular order. A round-robin method does not consider the availability, capacity, or location of the servers, and may assign requests to servers that are overloaded, offline, or far away. A round-robin method does not ensure that each node runs on a different physical server.
A live migration is a process that allows moving a running VM from one physical host to another without interrupting its operation. A live migration can improve the availability and performance of the VMs, as it enables dynamic load balancing, maintenance, and disaster recovery. However, a live migration does not prevent two or more VMs from running on the same physical host in the first place.
A priority queue is a data structure that stores elements based on their priority values. A priority queue allows inserting and removing elements in order of their priority, such that the element with the highest priority is always at the front of the queue. A priority queue can be used to implement scheduling algorithms for processes or tasks, but it does not affect where they run on physical servers.