Which combination of steps will meet these requirements?

Explanations:

While deploying instances across multiple Availability Zones can enhance availability and fault tolerance, it may not optimize the performance of an HPC cluster that relies on low-latency, high-bandwidth interconnectivity, which is better achieved by keeping instances within the same zone.

Deploying Amazon EC2 instances in a placement group allows the instances to be physically located close to one another within the same Availability Zone. This reduces network latency and increases bandwidth, optimizing the performance for HPC workloads.

Using Amazon EC2 instances that support Elastic Fabric Adapter (EFA) is critical for HPC applications requiring high throughput and low-latency networking. EFA provides a direct network path between instances and the network, which is essential for performance optimization in HPC environments.

Using burstable performance instances is not ideal for HPC workloads. These instances are designed for workloads that do not require sustained high CPU performance, which can lead to performance variability and does not align with the needs of HPC applications that require consistent, high performance.

Enabling CPU hyperthreading can improve performance for certain workloads, but HPC applications typically benefit more from physical core allocation rather than hyperthreaded cores. Additionally, the performance improvement from hyperthreading can vary based on the specific workloads being run.