HipLocal's requirement to troubleshoot occasional application failures in their APIs necessitates the collection of application-specific information. The most effective solution among the provided options is to install the Cloud Logging agent on the virtual machines. This action directly addresses the lack of logging in their existing environment by enabling the collection and analysis of application logs, which are crucial for identifying and resolving errors and exceptions. While options A, C, and D offer valuable functionalities, they do not specifically target the collection of application logs needed for troubleshooting application failures. Option A involves taking snapshots of virtual machines, which captures disk state but not runtime application behavior. Option C, installing the Cloud Monitoring agent, is more suited for collecting system metrics rather than application-specific logs. Option D, using Cloud Trace, is designed for latency analysis and not for error logging. Therefore, option B is the correct choice as it directly fulfills the need for application logging to troubleshoot failures.