Write an iterated integral for |dA over the region R described to the R right using a. vertical cross-sections, y =x b. horizontal cross-sections. y= x6 X a. Write the correct iterated integral using vertical cross-sections. Select the correct answer below and fill in the answer boxes to complete your choice. OA. J J ax dy OB. J J dy dx b. Write the correct iterated integral using horizontal cross-sections. Select the correct answer below and fill in the answer boxes to complete your choice. OA. J J dy dx 00 O B. S S ax dy 10