Concept:The integral represents the area under the curve y=9−x2 from x=0 to x=3.Explanation:The equation y=9−x2 can be squared to get x2+y2=9.This is a circle with center at the origin and radius r=3.Since y is positive, the curve gives only the upper half of the circle.The limits x=0 to x=3 cover the right quarter of that upper half.So the integral equals the area of one-fourth of the full circle.Area of the full circle is πr2=π(3)2=9π.Therefore, the required area is 41×9π=49π.Answer:∫039−x2dx=49πCorrect option: B. 49π