Right choice is (c) itemprop
Explanation: A boolean global attribute which specifies scope of associated metadata is itemscope. Itemmid is unique global identifier of item. To add a property to an item, the itemprop attribute is used on one of the item’s descendants. Markup without the microdata-related attributes does not have any effect on the microdata model. Itemref provides list of elements id’s with extra/additional properties in the document.