You create a custom page layout that has a field control named Field1.

You need to ensure that Field1 is only visible when users modify the contents of the page.

Which parent control should you use for Field1?

A.
EditModePanel

B.
PageLayoutValidator

C.
PublishingContext

D.
ValidatorAggregator

Explanation:
MNEMONIC RULE: “visible when modify = EditModePanel”

Provides a container that shows or hides its child controls based on the mode of the page.

EditModePanel Class
http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.publishing.webcontrols.editmodepanel.aspx