Predictions about the Cities of the Future

Câu hỏi: Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each the numbered blanks.
Cities are built to survive and prosper. Over the years, we have learned to___(39) ___ our surroundings according to our needs. We have cut through mountains to make more land and created artificial islands to make skyscrapers. City planning, as an organized profession, has existed for less than a century. ___(40) ___, a considerable amount of evidence proves the existence of fully planned cities in ancient times. Over the years, humans have made ___(41) ___ mistakes in terms of using an excessive amount of resources for cities. This gives rise to the question of how sustainable the cities of the future would be.
We might be looking at smart cities in ___(42) ___ street lights would only switch on when you are close by and traffic light would be eliminated by smart driving. The cities of the future would try to save our resources rather than deplete them.
An example of an advanced city is Kansas. Plans are in place to make Kansas a smart futuristic city in the future. Planners are considering introducing ___(43) ___ to monitor the water mains. Warning would be issued to city officials when the infrastructure requires repair or replacement. In this way, the city would never be at risk of having broken pipes.
The word or phrase which best fits the gap (43) is...
A. sense
B. sensors
C. activity
D. product