@phoenix_eD
Scenario 1 is definitely volume 38. It is the transition leading to the last arc with Buu.
Scenario 2 is volume 19, about 3/4 into the Saiyan arc (first arc after adulthood of Goku, where the last 4 surviving Saiyan appear).
Scenario 3 is volume 35, last volume of the Android/Cell...