Table:
text: List of A Pup Named Scooby-Doo episodes
Season 2: 1989
Season 2: 1989
Episode_title Villains Identityies Reasons Original_airdate DVD_volume
Night of the Living Burger The Burger Monster Skippy Johnson He wanted a raise from his employer. October 14, 1989 5
The Computer Walks Among Us The Computer Monster Bruce Wormsley He wanted to be the smartest kid in school. October 21, 1989 5
Dog Gone Scooby The Mad Scientist Paula P. Casso (Due to a misunderstanding) To make a painting of Scooby`s head. October 28, 1989 5
Terror, Thy Name is Zombo Zombo The Phantom Clown Joey Jipner To run the amusement park by himself. November 4, 1989 6

Question: How many DVD volumes did Skippy Johnson identify in the Season 2: 1989 A Pup Named Scooby-Doo episodes listing?