This is the net of a rectangular prism, so the surface area can be found with the formula: SA=2lw+2wh+2lh
In this case,
l=10.5
w=6.4
h=4
Now, we can plug these numbers into the equation:
SA= (2)(10.5)(6.4) + (2)(6.4)(4) + (2)(10.5)(4)
SA= 134.4 + 51.2 + 84
SA = 269.6 cm
Therefore, the answer is D.