Which of the following is/are NOT the step(s) used in separation and isolation of DNA fragments by gel electrophoresis technique:

(A) Staining with ethedium bromide
(B) Exposure to UV Radiation
(C) Cutting DNA fragments into small pieces by using restriction endonuclease
(D) Denaturation of DNA fragments

Choose the correct answer from the options given below:

(D) only

The correct answer is Option (1) → (D) only