Answer: C. 18 square unit.
Explanation:
Since, By the diagram we can say that,
The polygon is made by 4 rectangles in which,
Measurements of these rectangle are, 3 × 1, 4 × 1, 1 × 3, 4 × 2.
Thus, the total area of the given polygon = Total sum of the Area of these rectangles
A= 3 × 1 + 4 × 1 + 1 × 3 + 4 × 2= 3+4+3+8=18 square unit.
Thus, The area of given rectangle = 18 square unit.
Therefore Option C is correct.