What best describes the role of a Service Account in Google Cloud?

A Service Account in Google Cloud is primarily designed to allow applications and services to authenticate and interact with Google Cloud resources without requiring user intervention. This type of account is intended for server-to-server communication and is particularly useful when an application needs to perform actions on behalf of itself rather than a specific user.

When an application uses a Service Account, it can securely authenticate using the account's credentials, allowing it to access Google Cloud services like Cloud Storage, BigQuery, or Compute Engine without requiring a user's credentials. This facilitates automated workflows and enhances security by reducing the dependency on user accounts that may change or become inactive.

The other options do not accurately capture the primary function of a Service Account. While user authentication is important, it is not the main purpose of Service Accounts, which are geared toward non-human actors. Additionally, the role of Service Accounts is not limited to running virtual machines in Google Compute Engine; they can be utilized across various Google Cloud services. Similarly, while managing user permissions is crucial within IAM, Service Accounts are separate entities that support application-level authentication rather than directly managing permissions for users.