Choose the correct answer: A. carried out B. carried over C. carried off D. carry back

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Urbanisation programmes are being ___(28)___ in many parts of the world, especially in densely populated regions with limited land and resources. It is the natural outcome of economic development and ___(29)___.  It has brought a lot of benefits to our society. ___(30)___, it also poses various problems for local authorities and town planners in the process of maintaining sustainable urbanisation, especially in developing countries.

When too many people cram into a small area, urban infrastructure can't be effective. There will be a ___(31)___ of livable housing, energy and water supply. This will create overcrowded urban districts with no proper facilities.

Currently, fast urbanisation is taking place predominantly in developing countries where sustainable urbanisation has little relevance to people's lives. Their houses are just shabby slums with poor sanitation. Their children only manage to get basic education. Hence, the struggle for survival is their first priority rather than anything else. Only when the quality of their existence is improved can they seek ___(32)___ other high values in their life.

• A. carried out
• B. carried over 
• C. carried off 
• D. carry back