The correct answer is D because the M1 machine type is designed for memory-intensive workloads, providing a high memory-to-CPU ratio. This makes it ideal for applications requiring the full database to be stored in memory for fast access and minimal latency.

• A is incorrect as GPUs are for tasks requiring heavy parallel computing, not for improving RAM performance.
• B is incorrect because local SSDs, while offering high IOPS and low latency, are ephemeral and do not persist data after instance shutdown.
• C is incorrect since preemptible instances can shut down at any time, risking data loss for applications needing constant memory access.

For more details, refer to GCP's machine types documentation.