Answer:
The organizers of the contest put them together as a group and they win together.
Explanation:
In the given scenario, the tone of the story seems to be the united nature of the three girls. Being friends for over three years, and all good singers, they will be loyal to one another.
So, when they participate in the contest, it will be most satisfying for the readers to see them perform together instead of against one another. This will keep the friendship intact and also show that unity brings success and happiness, no matter what happens.
Thus, the most satisfying conclusion will be to see them put together as a group and win the contest.