Multiple choice technology mainframe 5 generations of a GDG already exist. Refer 1st generation in the JCL GDG (-4) GDG (-3) GDG (-5) GDG (1) Reveal answer Fill a bubble to check yourself A Correct answer Explanation In a GDG, (0) represents the current generation, (-1) the previous, and so on. For 5 existing generations, the relative generation numbers are (0), (-1), (-2), (-3), and (-4), making (-4) the oldest (first) generation.