Answer: B) two children pulling apart a wishbone
One person is on the left side, and the other person is on the right side. They pull in opposite directions to separate the bone. These forces counteract each other since they go in opposite directions.
In contrast, each of choice A, C, and D describe one or more forces that work together to go in the same direction. This could be a pulling force, or a pushing force, it doesn't matter either way. We can rule out choices A,C, and D for this reason.