Consider the following statements regarding digital signals:
$(i)$ provide a continuous set of values
(ii) represent values as discrete steps
(iii) can utilise binary system
(iv) are in the form of rectangular waves
Then the true statements are:

• A
  $(i)$,(ii)
• B
  (ii),(iii)
• C
  (ii),(iii),(iv)
• D
  $(i)$,(ii),(iii),(iv)