A widely cited study reports that exposure to greenery reduces self- reported stress in urban residents. The reported effect is robust across multiple cities. Critics, however, note that residents may already self-select into greener neighborhoods because they are less stressed to begin with — a possibility the original study did little to rule out.
Which choice best describes the function of the third sentence in the text?
- A
It strongly endorses the original finding.
- B
It defines the term 'greenery'.
- C
It introduces an unrelated finding.
- Dcheck_circle
It identifies a self-selection alternative explanation that complicates the causal interpretation.
Explanation
The critics' worry is a self-selection alternative undermining causal inference. B captures this complicating function.