On a mountain in China, the rivers in the north of the mountain freeze in winter, but in the south of the mountain; In the north of the mountain, jujube trees are in forests, peaches and plums are fragrant, and in the south of the mountain, rice fields are everywhere, and orange orchards are fragrant, so this article North of Qinling-Huaihe line is the north of China. Rivers freeze in winter, and the main economic trees are jujube, pear and peach. South of Qinling-Huaihe River is the south of China. In winter, rivers will not freeze, the main food crop is rice, and the main fruit is citrus. So option A.B.D doesn't fit the question.

So choose: C.