Which of the following conditions indicates bleeding upon probing?

Bleeding upon probing is a clinical indicator of inflammation in the periodontal tissues, which is a hallmark of gingivitis and other periodontal diseases. In the context of dental biofilm-induced gingivitis, inflammatory processes are triggered by the accumulation of dental biofilm (plaque) on the teeth and gums. This biofilm can lead to irritation and inflammation of the gingiva, resulting in symptoms such as redness, swelling, and importantly, bleeding when the tissues are probed.

In contrast, periodontal health and healthy gingiva are characterized by the absence of inflammation, where there will be no bleeding upon probing. Stage II periodontitis, while it may also show bleeding, typically involves more advanced tissue destruction and clinical findings beyond just bleeding, making it distinct from the gingival inflammation indicated in gingivitis. Therefore, the presence of bleeding upon probing specifically highlights the inflammation associated with dental biofilm-induced gingivitis, affirming it as the correct answer in this context.