Choose the missing terms out of the given alternatives.
AZ, BY, CX, ?
Choose the correct choice from the following choices
A) EF B) GH C) ED D) DW E) KN
D   DW   The first letter moves one step forward. The second letter moves one step backward.
<result>D</result>
Choose the missing terms out of the given alternatives.
AZ, BY, CX, ?