Dirt roads may evoke the bucolic simplicity of another

century, but financially strained townships point out

that dirt roads cost twice as much as maintaining

paved roads.

(A) dirt roads cost twice as much as maintaining

paved roads

(8) dirt roads cost twice as much to maintain as

paved roads do

(C) maintaining dirt roads costs twice as much as

paved roads do

(D) maintaining dirt roads costs twice as much as it

does for paved roads

(E) to maintain dirt roads costs twice as much as

for paved roads

Why is D wrong?