Answer: High Concurrency with Autoscaling

## Analysis of Requirements and Cluster Types ### Key Requirements: 1. **Minimize query latency** - Requires efficient resource allocation and scaling 2. **Maximize concurrent users** - Requires cluster sharing capabilities 3. **Reduce costs without compromising other requirements** - Requires intelligent resource management ### Cluster Mode Analysis: **Standard Cluster:** - Designed for single-user workloads - Cannot be shared by multiple users simultaneously - **Violates requirement #2** - Cannot maximize concurrent users **High Concurrency Cluster:** - Specifically designed for multiple users - Provides fine-grained sharing with Apache Spark fair scheduling - Optimized for minimizing query latency through efficient resource allocation - Supports user-defined functions and local processes ### Cost Optimization Mechanisms: **Autoscaling:** - Dynamically scales cluster size based on workload demand - Reduces costs by right-sizing resources - Maintains performance by scaling up during high demand - Does not compromise query latency or concurrent user capacity **Auto Termination:** - Terminates clusters after periods of inactivity - Can increase query latency due to cold starts - **Compromises requirement #1** when queries need to run - Not optimal for maximizing concurrent user access ### Optimal Selection Reasoning: **High Concurrency with Autoscaling (Option B)** is the correct choice because: - High Concurrency mode enables multiple users to run queries simultaneously - Autoscaling optimizes costs by dynamically adjusting cluster size - Maintains low query latency by scaling resources as needed - Does not compromise any of the three requirements **Why other options are suboptimal:** - **Standard clusters (A & D)**: Cannot support multiple concurrent users - **High Concurrency with Auto Termination (C)**: Auto termination can increase latency due to cluster restarts, compromising the first requirement The combination of High Concurrency mode with Autoscaling provides the best balance of performance, multi-user support, and cost efficiency without compromising any of the specified requirements.

Author: LeetQuiz Editorial Team