(单选题,2 分)(U7A 课文理解)"Rules restricting migrants' access to public services mean that some 250m people living in cities are second-class citizens, who could in theory be sent back to their home districts." What can we infer from this sentence?
选项：

A:All people have equal opportunities to enjoy the public services in cities.
B:Some migrant workers can also enjoy public services without any restrictions.
C:Migrant workers cannot enjoy some public services smoothly.
D:There are rules protecting migrant workers' access to public services.