What are the required label variables for sample bottles?

The correct choice highlights the significance of labeling sample bottles with specific information that ensures compliance with regulations and maintains the integrity of the samples. Indicating "Regulated Drinking Water Sample" on the label is crucial because it specifies the sample's purpose and context, which is important for regulatory processes and subsequent analysis.

Including the time on the label further enhances the traceability of the sample, allowing for accurate assessment and comparison of results over time. This is especially important in water quality analysis, where conditions can change rapidly, affecting the sample's properties and thus the results of any analyses performed.

While other options mention valid information, they do not encompass the regulatory context and necessary details that the label must convey for samples intended for drinking water testing.