Who uses this app play r o b l o cs

The answer is (A): with contextual tabs for major groupings of editing features and ribbons with specific groupings to organize commands.

Contextual tab or tabs are hidden menu that appears when objects like images or texts are selected in programs like MS Word 2013. They typically contain one or more commands applicable to a selected text or object only. They are there in the Ribbon when you need them and disappear when you do not need them anymore. They are basically used for major groupings of editing features.
A ribbon on the other hand help users understand how commands are used directly and efficiently. It organizes a program’s features into a series of tabs.