Please help me in this question

For security reasons, a company will enclose a rectangular area of 3,000 m in the rear of its plant. One side will be bounded by the building and the other three sides by fencing. If the bounding side of the building is 80 m long and 160 m of fencing will be used, what will be the dimensions of the rectangular area? Choose the correct answer below. A.30 m by 100 m B.30 m by 50 m C.50 m by 60 m D.60 m by 100 m