Answer: C.
Step-by-step explanation:
If the figure gets rotated 270ᴼ, then all of the transformed sides are perpendicular to the sides of the original figure.
The slope of DE is 2/4 (2 units up, 4 units over) or 1/2. If D’E’ is perpendicular to DE, then the slopes have negative reciprocals.
DE’s slope: 1/2
D’E’ slope: -2/1 or -2 (down 2, over 1)
