45. A smile can always _______ people.

(A)continue
(B)comment
(C) connect
(D)contribute
One area where 3D printing will be of immense _______ in the future is emergency
response infrastructure. Startups such as Texas-based ICON and California-based Mighty
Buildings use 3D printing to create buildings. ICON can build a 500-square-foot home in 24
hours, and Mighty Buildings structures require 95% fewer labor hours and generate ten
times less waste than conventional construction projects. The ability to quickly set up an
emergency response center or a portable hospital in response to a catastrophe is going to be
needed even more in the future. - John Cho, Peraton