You are given a sentence, a question and two answer options ('A' and 'B'). Your task is to find the correct answer (return the string of the correct option, not 'A' or 'B') for the given question.

Sentence: Mitch is rolling wagons down a hill at the same time. The red wagon goes to the bottom of the hill, but the black wagon stops halfway down the hill. Question: Which wagon was slower? (A) red wagon (B) black wagon
black wagon

Sentence: A spring rolling along a bed experiences very low friction, while one rolling along the floor experiences high friction. Question: Which surface is less rough? (A) floor (B) bed
bed

Sentence: A martial arts expert wants to demonstrate the force of his hands by striking a couple of boards. When stacked next to each other the white board is twice as tall as the red board. Question: Which board will be more difficult for the expert to break? (A) white board (B) red board

white board