Choose the correct form of the adjective:
1- 1- One of the most expensive cars ever sold at an auction was a 1962 Ferrari 250 GTO. The final price was $38,115,000.
2- 2- According to a research carried out in Scotland, music has a calming effect on dogs.
3- 3- An increase in the price of oil can cause instability, especially if it is a sudden increase like in the 1970s.
4- 4- It’s not easy to find good-quality shoes at prices.
5- 5- For a decade, the Chinese government has persuaded buyers and manufacturers into the vehicle market through subsidies and other incentives.
66- An American Marriage is a novel.
77- China's Chang'e-4 mission made a landing on the moon's far side.