which is the correct algebraic expression
please help image attached I'll give brainliest

Answer:
C. [tex]\frac{3}{2}ab - \frac{\pi a^2}{8}[/tex]
Step-by-step explanation:
Area triangle = [tex]\frac{1}{2}(3ab) = \frac{3ab}{2} = \frac{3}{2}ab[/tex]
Area semi-circle = [tex]\frac{1}{2}(\pi (\frac{1}{2}a)^2) = \frac{\pi (\frac{1}{2}a)^2}{2} = \frac{\pi (\frac{1}{4}a)^2}{2} = \frac{\pi a^2}{8}[/tex]
Final Equation = [tex]\frac{3}{2}ab - \frac{\pi a^2}{8}[/tex]
-Chetan K