Total surface area of a cuboid = 2(lb + bh + lh). Here lb=280, bh=30, and lh=336. So TSA = 2 × (280 + 30 + 336) = 1292 square cm. A cuboid has three pairs of equal rectangular faces: lb, bh, and lh. We add these three face areas and multiply by 2 to include the opposite faces. The answer is in square units, so the correct choice is 1292 cm².