The Datadog .NET Tracer for Windows applications writes its diagnostic logs to a dedicated directory by default. This location is %ProgramData%\Datadog .NET Tracer\logs\. This path is distinct from the Datadog Agent's log directory, allowing for separate troubleshooting of the tracer and the agent. While the location can be overridden with the DDTRACELOGDIRECTORY environment variable, the question asks for the default location.

B. This is the default log directory for the main Datadog Agent, not the specific .NET Tracer library.

C. This path uses a Linux/Unix forward-slash format and is the default location for the .NET Tracer on Linux systems, not Windows.

D. This is the specific log directory for .NET applications instrumented by Datadog within the Azure App Service environment.

1. Datadog Documentation, ".NET Tracer and Agent Logs". In the ".NET Tracer Logs" section, it explicitly states: "By default, the .NET Tracer's logs are located in %ProgramData%\Datadog .NET Tracer\logs\ on Windows". It also lists the paths for Linux and Azure App Service, confirming options C and D are for different environments.