Which of the following is a method for sending custom metrics to Datadog?

Sending custom metrics to Datadog can be achieved through various methods, and all the mentioned options are valid ways to do so.

StatsD is a network daemon that listens for statistics, like counters and timers, sent over UDP or TCP, and it aggregates them for reporting. Datadog has native support for StatsD, allowing it to receive and visualize these custom metrics seamlessly.

The Datadog API provides a robust way to send custom metrics programmatically. It allows developers to push metrics directly into Datadog using HTTP requests. This method is flexible and can be integrated with various programming environments, making it suitable for many use cases.

DogStatsD is an extension of StatsD specifically designed to integrate with Datadog. It allows users to take advantage of some advanced features like tagging and adding histograms, which enhance how metrics are collected and categorized.

Since StatsD, the Datadog API, and DogStatsD are all recognized methods for sending custom metrics to Datadog, it follows that all of them are valid options for this question. Thus, the choice indicating that all methods are ways to send custom metrics is correct.