More Americans were able to buy homes after the WWII because of the purchasing power of the American Dollar. In order for the country to experience a drastic economic change, it had to change its policies about taxes, cost of living, and personal wages of its people. So during that time period, people had a lot of money and decided to change their old ways of living in the city and moving into the suburbs to buy a lot and build their own houses there. They found that life was more peaceful and quaint as compared to the city life that's why there was a boom in suburban life after the WW.
It's not C because it doesn't say anything about the imperial court it's not A because the ex given in the passage was a scenario nor B because she said she imagined so its D :)