CLF-C02 Cloud Concepts Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Elasticity

  Why it's wrong here

  Elasticity is the ability of a system to automatically adjust compute capacity in response to changing demand, such as scaling out during traffic spikes and scaling in during lulls. The scenario describes placing instances in multiple Availability Zones behind a load balancer to maintain availability during an instance failure, but it does not mention any dynamic scaling policy, auto scaling group, or demand-based resource adjustment. Therefore, the described solution addresses redundancy for fault tolerance, not elasticity, which is specifically concerned with matching resource supply to workload fluctuations.

  When this WOULD be correct

  A company runs a web application on EC2 that experiences variable traffic. The application automatically adds instances during peak hours and removes them during low traffic using Auto Scaling. This demonstrates elasticity.

• ✓

  High availability

  Why this is correct

  Correct. High availability is the ability to keep applications running with minimal downtime by eliminating single points of failure. Placing instances in multiple Availability Zones behind a load balancer ensures that the application remains accessible even if one instance fails.

• ✗

  Scalability

  Why it's wrong here

  Scalability is the capacity of a system to handle increasing long-term load by adding resources, either through vertical scaling (larger instances) or horizontal scaling (more instances). The scenario focuses on continuing to serve users when a single instance fails, not on accommodating growth in user traffic or increasing overall capacity to meet rising demand. Adding an instance in another Availability Zone for redundancy does not inherently expand the system's maximum throughput or address growing workloads, so scalability is not the primary characteristic being fulfilled by this architecture.

  When this WOULD be correct

  A question describing an application that automatically adds EC2 instances during peak traffic hours and removes them during low traffic to maintain performance and optimize cost would demonstrate scalability.

• ✗

  Fault tolerance

  Why it's wrong here

  Although the scenario describes surviving an instance failure with minimal downtime, fault tolerance requires the system to continue operating without any interruption or degradation, whereas the described architecture allows for a brief period of disruption during failover. This option is tempting because fault tolerance is often associated with redundancy across Availability Zones, and it would be the correct choice if the application were designed to handle a failure with zero impact on performance or user sessions, rather than merely minimising downtime.

  When this WOULD be correct

  A question describing a system that continues operating without any interruption or data loss during a component failure, such as a multi-AZ database with synchronous replication or a fully redundant application with automatic failover that provides seamless continuity, would make fault tolerance the correct answer.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CLF-C02 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official CLF-C02blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”