Final answer:
To display the content of a folder in Windows OS via command prompt, the technician should use the dir command.
Step-by-step explanation:
If a technician is navigating through a Windows OS via command prompt and needs to display the content of a folder, the best command to accomplish this task is dir. The dir command is used to list the files and directories in the command prompt. Usage of the dir command will display all the contents of the folder, including files and subdirectories, along with details such as file sizes and modification dates.