Researchers Selected a Simple Random Sample of 4048 Medical Records

Researchers selected a simple random sample of 4048 medical records of adults diagnosed with gum disease. In all, 2226 were current smokers, 891 were former smokers, and 931 never smoked regularly. Their research question is, Do these data indicate that gum disease is equally likely regardless of smoking status? To test this null hypothesis of an equal representation of current, former, and never smokers among adults diagnosed with gum disease, how many degrees of freedom is associated with the chi-square statistic?

A) 1
B) 2
C) 3
D) 4