article: Dave Smith is 12. He has a sister. Her name is Sally. She is 8. Dave has a dictionary. It is blue. The dictionary is in his black backpack. He has a computer game and he likes it. Sally has a watch. It is red. She likes it very much. She has a nice pencil box, too. It is white. Her pencil, ruler, eraser and pen are in the pencil box. Her pencil box is in the yellow backpack.
question: What color is Dave's backpack?
options: Black. Blue. Red. Yellow.