Answer:
B. 180
Detailed working and explanation
Divide the irregular figure into 2. You should have a rectangle and a parallelogram.
Total area of irregular figure
=Area of parallelogram+Area of Rectangle
Where Area of parallelogram=bh
area of Rectangle=lw
=(12×*(15-6))+(12×6)
=(12×9)+72
=180mm²
*Note how the parallelograms height was calculated