Choose Scaled and, depending on the size of your Retina display, you'll have four or five options. On the Display tab, you'll see two options at the top of the window for Resolution: Default for display and Scaled. Open System Preferences and go to Displays. Retina displays offer what Apple calls 'scaled resolutions' to bump up size of text and icons. That's never a great idea anyway because you lose sharpness in the bargain for larger, more legible letters. For Macs with Retina displays, you can't lower the native resolution to a specific resolution in order to increase the size of text and icons like you can on other laptops and displays.
