Explanation:

- Cloud computing is an Internet-based computing model. It provides various computer processing resources and data on demand.

- Users and enterprises gain capabilities for data storage and processing at third-party data centers.

- This reduces the workload on local computers for running applications.

- Cloud computing applies high-performance computing power to consumer-oriented applications like financial calculations.

- It offers personalized information delivery and data storage solutions.

- In 2013, cloud computing was highly demanded due to benefits like high computing power, affordability, scalability, and accessibility.

- Option 1: Authentication typically refers to verifying someone's identity, not describing a service.

- Option 3: Performance describes capability but not a service or product.

- Option 4: Subscription refers to paying regularly for a service but doesn’t fit the context as well.

- Correct Answer: Option 2: Utility

- Cloud computing is often described as a utility service because it provides resources efficiently and on-demand, much like utilities such as electricity or water.