The best solution to resolve the issue of network slowness caused by high uplink bandwidth utilization on the core switch is to enable quality of service (QoS) to prioritize production traffic over other types of traffic. QoS is a mechanism that allows network administrators to classify and manage network traffic according to its importance, latency, bandwidth, and reliability requirements. By enabling QoS, the core switch can allocate more resources and guarantee better performance for production traffic, while limiting or dropping less critical traffic. Reference: CompTIA Cloud+ Certification Exam Objectives, Domain 4.0 Troubleshooting, Objective 4.1 Given a scenario, troubleshoot connectivity issues related to cloud implementations.

Explanation
The correct answer is D. Migrate the data to flash storage. Flash storage is a type of solid-state storage that uses flash memory to store data. Flash storage has much faster performance and lower latency than NL-SAS storage, which is a type of hard disk drive that uses nearline serial attached SCSI interface. According to the web search results, NL-SAS devices have much higher response times than flash devices123. Therefore, migrating the data to flash storage can reduce the application latency and improve the user experience.
Increasing the capacity of the data storage, migrating the data to SAS storage, or increasing the CPU of the VM are not likely to solve the latency issue, as they do not address the root cause of the problem, which is the slow performance of NL-SAS storage. For more information on flash storage and its benefits, you can refer to the Dell EMC Unity: FAST Technology Overview2 or the Dell Technologies website4.