https://www.cisco.com/c/dam/en/us/solutions/collateral/data-center-virtualization/desktop- virtualization-solutions-vmware-horizon-view/whitepaper-c11-741606.pdf

The performance issue is caused by the high demand of complex SQL queries on the database server, which consumes a lot of RAM and disk throughput. Increasing caching on the database server would reduce the number of disk reads and writes, as well as improve the response time of the queries by storing frequently accessed data in memory. This would be the best solution to resolve the performance issue.
Reference: CompTIA Cloud+ Certification Exam Objectives, Domain 4.0 Troubleshooting, Objective 4.3 Given a scenario, troubleshoot capacity issues within a cloud environment.

Explanation
The most likely causes of the issue where the new asynchronous workflow fails to create 50 VMs at once in the public cloud are insufficient storage and expired API token. Insufficient storage means that there is not enough disk space available in the public cloud to accommodate all the VMs that are being created simultaneously. This could result in errors or failures during the provisioning process. Expired API token means that the authentication credential that is used by the workflow to communicate with the public cloud service has expired or become invalid. This could result in errors or failures during the API calls or requests.
Reference: CompTIA Cloud+ Certification Exam Objectives, Domain 4.0 Troubleshooting, Objective 4.5 Given a scenario, troubleshoot automation/orchestration issues.

Documenting the solution and placing it in a shared knowledge base is what the administrator should do next after troubleshooting performance issues with a VDI (Virtual Desktop Infrastructure) environment, determining that the issue is GPU (Graphics Processing Unit) related, increasing the frame buffer on the virtual machines, and testing that confirms that the issue is solved and everything is now working correctly.
Documenting the solution is a process of recording and describing what was done to fix or resolve an issue, such as actions, steps, methods, etc., as well as why and how it worked. Placing it in a shared knowledge base is a process of storing and organizing documented solutions in a central location or repository that can be accessed and used by others. Documenting the solution and placing it in a shared knowledge base can provide benefits such as:
* Learning: Documenting the solution and placing it in a shared knowledge base can help to learn from past experiences and improve skills and knowledge.
* Sharing: Documenting the solution and placing it in a shared knowledge base can help to share information and insights with others who may face similar issues or situations.
* Reusing: Documenting the solution and placing it in a shared knowledge base can help to reuse existing solutions for future issues or situations.

Explanation
Vendor lock-in is a situation where a customer becomes dependent on a specific vendor for products or services and faces high switching costs or barriers when trying to change vendors. Vendor lock-in is most likely to be a concern for a company that developed a product using a cloud provider's PaaS platform and many of the platform-based components within the application environment when utilizing a multicloud strategy or migrating to another cloud provider, as it can limit the flexibility, scalability, and portability of the product and increase the complexity, risk, and cost of moving or integrating with other cloud platforms or providers. References: CompTIA Cloud+ Certification Exam Objectives, page 8, section 1.2