A boat sails directly toward a 150-m skyscraper that stands on the edge of a harbor. The angular size of the building is the angle formed by lines from the top and bottom of the building to the observer (see figure). Complete parts a and b below. (Round to five decimal places as needed.) b. Graph de dx as a function of x and determine the point at which the angular size changes most rapidly. Choose the correct graph below. OA [0,1000] by [0.0.008] OB OD. 150 m (0,1000] by (0,0.008) (0,1000] by [-0.008,01 (0,1000] by [-0.008,01 For what value of x is the angular size changing most rapidly? x=(Round to the nearest integer as needed.)