The girl came from the countryside to go to school in the city, and her classmates laughed at his accent.

According to the description of the topic, Xiaowen's experience shows that inequality still exists in social life, and urban students can't correctly treat the differences with Xiaowen, which leads to these differences becoming the root of discrimination against Xiaowen, so 3④ is the correct option, 1② is the wrong view, and the option ABD is excluded. Including 1②.

So choose C.