Final answer:
Smoking is a risk factor that increases the probability of clinical attachment loss, harming oral health by promoting periodontal diseases.
Step-by-step explanation:
The risk factor from the provided options that increases an individual's probability of clinical attachment loss is b. Smoking. Smoking contributes to several oral health issues, including the inflammation and erosion of gums, which can lead to periodontitis. This disease is characterized by the recession of gums and the destruction of the structures that support the teeth, leading to clinical attachment loss. On the contrary, options such as regular dental check-ups, good oral hygiene, and consuming calcium-rich foods are beneficial to oral health and can help prevent dental issues like caries, tartar, and gingivitis.