
Hawkmoon269 |

The random card comes from your class deck. It can't be of a higher deck number than the scenario that awards it.
Guide to Organized Play p7 wrote:
Earning Scenario Rewards
The biggest change in Adventure Card Guild play is the method for improving your deck after completing a scenario. This happens in two steps: earning scenario rewards and upgrading your deck.
The procedure for earning scenario rewards (or adventure rewards, or adventure path rewards) follows the standard rules with one exception: If you are rewarded with a card from the box, you will instead take a random card of the same type from your Class Deck box. The card you take cannot have an adventure deck number higher than that of the scenario you completed. For example, if you just completed a scenario in adventure 2, and the scenario reward was a random item from the box, you would instead take an item with an adventure deck number no higher than 2 from your Class Deck. If you do not have an appropriate item, you do not gain that reward.

skizzerz |
Pathfinder Adventure, Adventure Path, Lost Omens, Maps, PF Special Edition, Starfinder Adventure Path, Starfinder Maps, Starfinder Roleplaying Game Subscriber

No, you only remove basics and elites from the box, class decks remain fully intact. This means you can still get a Basic B as a random reward even in adventure 3 or 4.