Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage. 

There are 21.900 households in an area of less than 100 hectares of the Old Quarter in Ha Noi. In many houses, an entire family may (1) _____ no more than a single room.

A house on Hang Ca Street (2) ________ in the 1940s originally belonged to one wealthy man and his wives, and now there are six households there with about 30 people. Many say the convenience of the Old Quarter (3) _______ compensates for the shortage of facilities. Tradition is also a(n) (4) _______ because some residents have (5) _____ houses elsewhere but no one wants to sell the old houses or rooms (6) ______ these are the houses of the ancestors.

The authorities of Ha Noi have had a plan to (7) _______ 25,000 of the Old Quarter’s 54.000 residents, beginning in 2009 when 1.900 households will go to a new development area, across the Red River.

However, people don’t want to live in a high-rise block because they (8) _________ to it. Authorities will take (9) ______ to find out what people will need to (10) _______ them feel comfortable in their new neighbourhood.

Tradition is also a(n) (4) _______ because...