Which of the following LCD provides the HIGHEST contrast (the darkest black and lightest white)?

OLED (Organic LED) displays are not LCD (Liquid Crystal Display) displays. Each of the other three has a distinct advantage. The fastest refresh rates are on TN (Twisted Nematic) displays, the best viewing angle is on IPS (In-Plane Switching) displays, and the best color contrast is on VA (Vertical Alignment) displays.