Which of the following figures will complete the given figure in such a way that the area is $4 \mathrm{sq}. \mathrm{units}$?

Given:

We have to complete the figure in such a way that the area is $4 \mathrm{sq}. \mathrm{units}$.

Now, let us find the area of the figures given in the option.

Area of the figure in option A will be:

$$\begin{gathered} =\frac{1}{2}+\frac{1}{2}+\frac{1}{2}+\frac{1}{2}+1+1 \\ =4 \mathrm{sq} \mathrm{units} \end{gathered}$$

Area of the figure in option B will be:

$$\begin{gathered} =\frac{1}{2}+\frac{1}{2}+\frac{1}{2}+\frac{1}{2}+1+1 \\ =4 \mathrm{sq} \mathrm{units} \end{gathered}$$

Hence, option C is correct.