The answer is A, because: The dimentions in cm are 5cm by 3cm, so you make that to scale. The page says that 1cm is equal to 5m, so you multiply both numbers by 5 and you get 25 by 15. If you need clarification, let me know.
The answer is a because to get the length of the sides you do 7-4 which is 3 times five is 15m. To find the base you do 2 times 3 times 5 which is 25m.
A) 25m. * 5m.