At a local plant sale, Janice was selling Golden Barrel Cactus plants and baby Saguaros. During the sale, she sold 5 times as many Saguaros ($6 each) as Golden Barrels ($10 each). She made a total of $720 during the plant sale. How many Saguaros did Janice sell? A. 18 B. 40 C. 72 D. 90