Two prisms are composed to form a V shape. The thickness of each prism is 1 unit, and width of each prism is 2 units. If the length of one prism is greater than the length of the other prism by 1 unit and the total volume of the figure is 30 cubic units, what are the lengths of the prisms? A. 7 units and 8 units B. 5 units and 6 units C. 3.5 units and 4 units D. 2.5 units and 4 units