The periodontal health status of former smokers is not as good as that of never smokers. The periodontal health status of former smokers is better than that of current smokers.
a. The periodontal health status of former smokers is better than that of current smokers, but not as good as that of never smokers.
b. The periodontal health status of former smokers is not as good as that of current smokers, and also not as good as that of never smokers.
c. The periodontal health status of former smokers is better than that of never smokers, but not as good as that of current smokers.
d. The periodontal health status of former smokers is not as good as that of current smokers, but better than that of never smokers.