A Study Demonstrates That the Number of Cigarettes Smoked Per

Multiple Choice

A study demonstrates that the number of cigarettes smoked per day is significantly correlated with the number of respiratory infections experienced by young adults.This observation suggests that

A) cigarette smoking causes respiratory infections.
B) cigarette smoking does not cause respiratory infections.
C) cigarette smoking causes some respiratory infections but not others.
D) the data do not allow inferences about causation.