surface area is the area of the surfaces
the areas are
base
2 triangles (faces)
2 rectangluar sides
solve
area of base=legnth times width=16 times 9=144
area of 2 triangles is 2 times 1/2 times base times height=2 times 1/2 times 16 times 6=1 times 16 times 6=96
area of 2 rectangles=2 times legnth times width=2 times 10 times 9=180
total area=base+2 triangles+2 rectangles
total area=144+96+180=420 square inches
the answer is 420 square inches or B