【单选题】

Chicago

Chicago, lying in the east of the USA, is the rather youngAmerican city. It was almost completely rebuilt after the Great Fire of 1871. One’s first impression of the city may include streams of cars running to-and-fro on the highways, skyscrapers and the wide green water of Lake Michigan, which lies to the northeast of the city. The area of the city is over 228 square miles with a population of about 3 million.
The climate ofChicago on the whole is almost the same as that ofBeijing with rather hot days in summer, colorful and fresh days in fall and icy but often clear days in winter. The spring inChicago is a little changeable in temperature. For instance, I saw a snowfall in earlyApril this year while some of the flowers were already in full bloom.Chicago is also famous for its frequent strong winds, and as a result has got the name of "the WindyCity".
In the passage you read "... colorful and fresh days in fall." Which of the following sentences carries the closest meaningA．in the season that has either snowfall or rainfall
B．in the days which has either snowfall or rainfall
C．in the days which are colorful and fresh