What kind of disorder is dyslexia

A．They are visual letters.
B．They are represented by sounds.
C．They are sounds represented by letters.
D．They are signs called letters.

A．Man would have to use war signals.
B．Man would have to stop inventing things.
C．Man wound not be able to live his fellow beings.
D．The world would be a place without universities, business contracts and newspapers.