Your published layout.cshtml file contains a static placeholder with a “main” placeholder key and you want to add renderings to the presentation details of a templates standard values; however you cannot see the "main" placeholder key you added to the layout. Of the available options, which is the best explanation of what happened?

Your published layout.cshtml file contains a static placeholder with a “main” placeholder key and you want to add renderings to the presentation details of a templates standard values; however you cannot see the "main" placeholder key you added to the layout. Of the available options, which is the best explanation of what happened?
A . There is a missing configuration element in web.config for placeholders.
B. The wrong layout is associated with the current template.
C. A Sitecore publish is required to show placeholder keys when editing presentation details.
D. There is no placeholder settings item for the associated "main" placeholder key.

Answer: D