Final answer:
Bubbles in both physical and logical data flow diagrams are labelled with nouns, representing either the data being processed or the function of the process. Thus, the correct answer is 'both physical and logical data flow diagrams'.
Step-by-step explanation:
The question pertains to data flow diagrams (DFDs), which are used in the analysis and design of information systems to depict the flow of data within a system. DFDs are categorized into two types: physical and logical. Physical DFDs describe how the system will be implemented, including hardware, software, files, and people involved. Logical DFDs focus on what happens to data as it moves through the system, ignoring the physical aspects of implementation.
In the context of DFDs, bubbles represent processes that transform data inputs into outputs. Bubbles are labelled with nouns that typically represent the data being processed or the function of the process in a logical data flow diagram. In contrast, the labels in physical DFDs often include verbs because they depict the actions performed on the data by system components.
Therefore, the correct answer is c. both physical and logical data flow diagrams, as both types of diagrams include processes represented by bubbles, which are labelled with nouns describing the data or information.