Part A: Net A is correct Net B is incorrect because de triangular sides do not close the opening left in both sides.
Part B: AB=3 in., BC=5in., CD=8.6in.
Part C: The surface area of the prism is the area of the the big rectangle in the net + the area of the 2 triangles
Area of the big rectangle 8.6• ( 3+4+5)= 103.2 in ^2 Area of the triangles If we get the 2 trangles together along their longest side we get another rectangle 3•4 =12 in^2