A Hypothesis Is That That Spending Time Hiking in the Woods

Multiple Choice

A hypothesis is that that spending time hiking in the woods improves seasonal allergies .Hikers and non-hikers were surveyed, and hikers were found to have fewer seasonal allergies .People with allergies may choose not to hike in the woods .This is an example of

A) Reverse causation
B) Common cause
C) Sample selection bias
D) All of the above