A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 560 sq. feet, how many feet of fencing will be required?
Select the correct option.
A) 34  B) 40  C) 68  D) 76  E) 92

Rationale: "given that length and area , so we can find the breadth . length x breadth = area 20 x breadth = 560 breadth = 28 feet area to be fenced = 2 b + l = 2 ( 28 ) + 20 = 76 feet answer : d"
Answer: D