When does an umpire need to blow their whistle during a stoppage?

The correct answer is that umpires need to blow their whistle to signal the start of play and after a goal. This action is essential in netball for maintaining the flow and structure of the game.

When the game starts or resumes after a stoppage, the whistle signals to the players that they can commence play. Similarly, after a goal is scored, the umpire blows the whistle to indicate that the game is stopping momentarily to reset for the next center pass. This ensures that all players are aware of when to begin or resume playing, reinforcing the orderly progression of the match.

The other options do not accurately capture the role of the umpire in managing stoppages. Ending the game is more about the final whistle rather than managing regular play interruptions, and the beginning of the half is just one specific instance rather than a full description of all stoppage scenarios. Lastly, a team requesting a stoppage doesn't require the umpire to blow their whistle unless it pertains to specific game rules, which may not encompass all stoppage situations.