![](https://cos-cdn.shuashuati.com/pipixue-wap/2020-1230-1107-56/ti_inject-812ce.png)
Identify the connections between the ideas from the three sources above.
A.
All the three sources focus on the changes of air pollution.
B.
Source 1 and Source 2 focus on the deterioration of air pollution.
C.
Source 3, different from Source 1 and Source 2, focuses on the reduction of air pollution.