Which of the following is considered a complex field and should not be rendered using...

Image is considered a complex field in Sitecore MVC because it requires additional parameters and logic to render properly, such as the image source, width, height, alt text, and so on. The Html.Sitecore().Field() method is designed for simple fields that only need the field name and value to render. For complex fields, you should use the Html.Sitecore().Rendering() method instead, which allows you to specify the rendering parameters and the rendering item for the field. Alternatively, you can use the Sitecore MVC helpers, such as @Html.Sitecore().Image(), to render complex fields with more control and flexibility. References:

[Sitecore 10 .NET Developer Certification Study Guide], page 17

[Sitecore Documentation: Rendering complex fields]