x How does the last sentence in paragraph 7 refine a key concept about
road construction?
A
The cost of the latest technology delays plans for
building safer and more durable roads.
B
Solar roads provide a less costly solution to building
safe and fuel-saving roads.
C
Energy-saving techniques used in road construction
are not available in the near future.
D
The cost of construction poses an obstacle to
building safer and more durable roads.