CONCEPT: The question tests on the basics of Geometry
Perimeter of the rectangle = 2*(L+B)
= 2*(8+5)=26 units
Given, the parallelogram has the same perimeter as the rectangle.
Hence, GF + FE + ED + DG = 26
Opposite sides are congruent and hence we can rewrite the equation as
6 + EF +6 +DG = 26 =>EF + DG =14 and since opposite sides are congruent
We have EF = 14/2 = 7 units. (OPTION B)