In the following passage, some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.
Inhabitants of the Earth have cleared ________ forests to make fields for growing crops. They have moved mountains to make ________ for roads and cities. They have built huge dams ________ rivers to turn valleys into lakes and they have built dykes to push back the sea and create more dry land to live on. Once everyone cheered at the progress that man made in changing his _________ like this, but now many people are worried by the ___________ that such changes can bring.
many people are worried by the ___________ that such changes can bring.

Options

A. benefits
B. advantages
C. agreements
D. problems

Answer

D