The correct answer is Mail.Outlook organizes your emails, calendars, contacts, tasks, and to-do lists, all in one place. The quick access bar is an important part of your Outlook experience. And it's an easy way to move among the top Outlook features”Mail, Calendar, People, and Tasks. The bar is in addition to the standard tabs and ribbons that provide an assortment of tools and options to help use and manage Outlook.?Additional InformationReading Pane in Outlook can help users preview items in the Inbox without opening them. The text of messages is displayed in the reading pane and it is of safety to open attachment, follow hyperlinks, and respond to meeting requests in the reading pane.The To-Do Bar consists of four parts ” the Date Navigator, the Appointments section, the Task List, and Quick Contacts. You can resize or hide each part.The button to hide, minimize, or maximize the People Pane is on the right side of the View ribbon.