Answer:
The correct answer is B) background distressors.
Explanation:
As Rudy lives in a run-down building behind the train depot which shows that he is living in a poor and unhygienic condition so there can be several factors which can be responsible for the upper respiratory infection in Rudy, for example, the area can be dusty which is causing respiratory problems or it contains toxic substances or microbes, molds, etc.
So the cause of his respiratory illness can be due to any environmental factor but it is not known exactly therefore his recurrent illnesses are likely due to background disstressors.
