A and B are two consecutive letters of the alphabet that are far apart on a QWERTY keyboard.

Q W E R T Y U I O P
 A S D F G H J K L
  Z X C V B N M

C and D are two consecutive letters of the alphabet that are very close on a QWERTY keyboard.

Q W E R T Y U I O P
 A S D F G H J K L
  Z X C V B N M

Which two consecutive letters of the alphabet are the farthest apart on a QWERTY keyboard?