Implement scheduled batch jobs with many interdependent steps (shell scripts, Hadoop jobs, BigQuery queries), long runtimes, and fixed retry counts. Which service should orchestrate and manage these workflows?

Cloud Composer is the correct choice because it is a fully managed Apache Airflow service, ideal for orchestrating complex, multi-step workflows like those described. Airflow's directed acyclic graphs (DAGs) allow you to define dependencies between tasks (shell scripts, Hadoop jobs, BigQuery queries), manage retries, and monitor execution. Cloud Scheduler is for simple, time-based job triggering, not complex orchestration. Cloud Dataflow is a managed service for executing data processing pipelines, not for orchestrating diverse job types. Cloud Functions are event-driven serverless functions, suitable for small, single-purpose tasks, not for managing interdependent batch jobs with long runtimes.