Answer:
Smallest surface area is of Cuboid B i.e 440 cm²
So, The company will choose cuboid B
Step-by-step explanation:
We need to find the surface area of all cuboids.
Surface Area of Cuboid A:
Length = 6
Breadth = 25
Height = 4
The formula used is: 
Putting values and finding surface area:

So, Surface Area of Cuboid A = 548 cm²
Surface Area of Cuboid B:
Length = 10
Breadth = 6
Height = 10
The formula used is: 
Putting values and finding surface area:

So, Surface Area of Cuboid B = 440 cm²
Surface Area of Cuboid C:
Length = 2
Breadth = 20
Height = 15
The formula used is: 
Putting values and finding surface area:

So, Surface Area of Cuboid C = 740 cm²
So, We get:
Surface Area of Cuboid A = 548 cm²
Surface Area of Cuboid B = 440 cm²
Surface Area of Cuboid C = 740 cm²
The company wants to choose the design having smallest surface area.
So, smallest surface area is of Cuboid B i.e 440 cm²
So, The company will choose cuboid B