The answer is C. 94 ´ 94 ; 8836 ft.
There are 4 possible gardens, each with different areas. From the biggest area to the smallest one:
8836 ft (C.) > 8835 ft (D.) > 8832 ft (B.) > 8811 ft (A.)
Thus, the greatest possible area for a garden will be 8836 ft (choice B.). It should also be taken into consideration that this is a square ( 94 ´ 94 ) which is for surely rectangle.