Which One of the Following Statements Is True Regarding Layout

Multiple Choice

Which one of the following statements is true regarding layout update handles?

A) Layout update handles must always match a module_controller_action pattern such as catalog_product_view.
B) There may never be more than one layout update handle per request.
C) Layout update handles are declared at any level of the layout XML hierarchy.
D) A layout update handle may be specified as a string argument when calling loadLayout ( ) .