An open source monitoring and alerting toolkit that collects metrics from various services and offers querying and alerting is the correct option.

Prometheus collects time series metrics from instrumented applications and exporters using a pull model and it stores those metrics so you can run ad hoc and continuous queries. It provides a powerful query language called PromQL that you can use to build dashboards and drive alerting rules, and it integrates with Alertmanager to manage notification workflows.

In cloud native environments at a company like example.com Prometheus typically serves as the central metrics store for service health and performance monitoring. Teams use it to define alerts, drive dashboards in tools like Grafana, and support SLO and capacity planning work.

Argo CD is incorrect because it is a GitOps continuous delivery tool for deploying applications to Kubernetes and it does not provide Prometheus style metric collection or alerting.

Google Cloud Storage is incorrect because it is an object storage service and it does not perform monitoring or alerting functions.

A programming language for Kubernetes development is incorrect because Prometheus is a monitoring system and not a programming language.

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