Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.

Unlike life in the countryside, which is often considered to be simple and traditional, life in the city is modem and complicated. People from different regions move to cities in the hope of having a better life for themselves and their children. With plenty of job opportunities available in the city, the inhabitants work as secretaries, businessmen, teachers, government officials, factory workers, street vendors or construction workers and so on.

The high cost of living requires city dwellers, especially those with low income, to work harder or to take part-time jobs. For many people, daily life typically involves getting up in the early morning to do exercise in public parks, preparing for a hard day of working and studying, then travelling along crowded boulevards or narrow streets filled with motor scooters and returning home late at night. They usually live in large houses, high-rise apartment blocks or even in small rental rooms equipped with modem facilities, like the Internet, telephone, television, and so on. Industrialization and modernization, as well as global integration, have big impacts on lifestyle in cities. The most noticeable impact is the Western style of clothes. The “Ao dai” - Vietnamese traditional clothes - is no longer regularly worn in Vietnamese women’s daily life. Instead, jeans, T-shirts and fashionable clothes are widely preferred.

These factors contribute _________ making city life more difficult for its residents. A. with B. in C. on D. to