Alpha led GREEN 1, and the team task requires Alpha to win the trick containing GREEN 1. I am void in GREEN, so I must discard. Any BLUE I play won’t affect the trick unless someone plays a ROCKET, which would jeopardize the task—so I should make a safe, low discard. I hold all remaining BLUEs (5,6,7), so preserving the higher BLUEs (6,7) keeps endgame control for the final two tricks if we need it. Therefore, discard the lowest: BLUE 5.