Answer: Identify the number of virtual cores and RAM associated with the application server virtual machines align them to a custom machine type in the cloud, monitor performance, and scale the machine types up until the desired performance is reached.

The correct answer is D because it aligns with Google Cloud's best practices for migration and rightsizing. Option D recommends identifying the virtual cores and RAM of the existing application server virtual machines (VMs) and mapping them to custom machine types in GCP, followed by monitoring and scaling. This approach ensures a baseline performance similar to on-premises while allowing optimization based on actual cloud performance. The community discussion supports D with high upvotes (e.g., 42 upvotes for a comment favoring D) and references to Google's migration documentation, which emphasizes starting with a like-for-like mapping and then adjusting. Option A is less suitable as it focuses on physical hardware, which may not accurately reflect VM requirements. Option B is incorrect as it suggests a fixed high RAM-to-CPU ratio without considering actual needs. Option C is problematic because it recommends deploying the smallest instances into production, which could cause performance issues and is not aligned with the case study's focus on migrating test/dev environments first.

Author: LeetQuiz Editorial Team