The hole in the ground was too big, so the boys couldn't get inside the cave.
It would most likely be determining how to improve meals at the school cafeteria
C. Theme
A purpose is the point or intention of the writing piece, it doesn't always tie the writing together. The genre is the type of writing, like fantasy, science fiction etc and the plot is the story/narrative itself. Therefore A, B and D are incorrect.
I think the answer is B. hope I could help. :)