Answer: Configure Lambda SnapStart.

**Explanation:** **Why D (Configure Lambda SnapStart) is correct:** 1. **Lambda SnapStart** is specifically designed for Java 11 (and later) Lambda functions to reduce cold start latency by taking a snapshot of the initialized execution environment after the first invocation. 2. **Cost-effectiveness**: SnapStart doesn't incur additional costs like provisioned concurrency. It reduces cold starts without requiring you to pay for pre-warmed capacity. 3. **Java-specific optimization**: Java applications typically have longer cold starts due to JVM initialization, and SnapStart addresses this by reusing snapshots. 4. **Matches requirements**: The company wants to reduce cold starts and outlier latencies when scaling up, and doesn't have strict latency requirements, making SnapStart ideal. **Why other options are incorrect:** - **A (Configure Lambda provisioned concurrency)**: While this reduces cold starts by keeping functions warm, it's more expensive as you pay for provisioned capacity even when not in use. Not the most cost-effective solution. - **B (Increase the timeout of the Lambda functions)**: This doesn't address cold start latency at all. Timeout only controls how long a function can run, not startup time. - **C (Increase the memory of the Lambda functions)**: While more memory can slightly improve performance, it doesn't specifically target Java cold start issues and increases costs without directly addressing the core problem. **Key considerations:** - Lambda SnapStart is free and specifically optimized for Java runtime cold starts - Provisioned concurrency is better for strict latency requirements but costs more - The question emphasizes "MOST cost-effectively" which makes SnapStart the clear choice

Author: LeetQuiz Editorial Team