Final answer:
The 'portal preview' is the option that allows one to see a rendering of campaign content as it will be displayed to employees. This tool is crucial for ensuring that the campaign content appears correctly across different devices and platforms.
Step-by-step explanation:
The option that displays a rendering of campaign content to allow you to see how your campaign will be viewed by the employee is portal preview. When you are running a campaign, it's important to ensure that the content appears as intended on various devices and platforms that the employees might use. A portal preview function allows you to view the campaign exactly as it would appear to the employees, helping you to catch any potential issues with formatting or content before the campaign goes live. This tool is integral in the campaign creation process as it provides a realistic visual of the campaign's user experience.