I see two shapes in the given figure. A rectangle and a triangle.
We need to get the area of the rectangle and triangle. We then deduct the area of the triangle from the area of the rectangle to get the area of the shaded portion.
Area of the rectangle = length * width
A = 11 mm * 10 mm
A = 110 mm²
Area of the triangle = (hb)/2
A = [(11mm-7mm)(10mm)] ÷ 2
A = (4mm*10mm) / 2
A = 40mm²/2
A = 20mm²
110 mm² - 20mm² = 90 mm² Choice A.