Read the following passage and mark the letter A, B, C, or D on your answer sheet to choose the word or phrase that best fits each of the numbered blanks from 36 to 40.

COPING WITH TRAFFIC
Many large cities around the world have struggled to keep up with the increase in traffic in recent times. Densely populated areas, growing car ownership, as well as narrow roads brought for much lower volumes of traffic all (36) _______ to this. In 1975, Singapore decided to introduce a congestion charge - a (37) _______ paid by drivers entering the most traffic-heavy zones of the city. London introduced a congestion charge in 2003.
Public opinion was initially opposed to the idea, (38) _______ people soon became more supportive of the scheme. Despite this, its first decade brought mixed success, and the (39) _______ of cars in the city fell by only 10%. However, the scheme proved massively profitable, (40) _______ allowed the city council to invest in other measures aimed at improving traffic conditions in London. These included cycle lanes, pedestrianized areas and better road surfaces.