Answer: Option 'C' is correct.
Explanation:
Since we have given that
Dimensions of I st box as shown in the figure below:
Length = 5 units
Width = 2 units
So, Area of Ist box will be given as

Dimensions of II nd box as shown in the figure below:
Length = 2 units
Width = 1 unit
So, Area of II nd box will be given as

Similarly,
Dimensions of III rd box as shown in the figure below:
Length = 3 units
Width = 2 units
So, Area of III rd box will be given as

Total area of the polygon will be

Hence, Option 'C' is correct.