Final answer:
The degree to which information includes all necessary data about relevant objects or events for decision-making is referred to as completeness. It ensures that decisions are made with the most complete information available, despite often dealing with imperfect data in reality.
Step-by-step explanation:
The degree to which information includes data about every relevant object or event necessary to make a decision is C. completeness. Completeness in this context means that all the necessary information is present to evaluate a situation and make a fully informed decision. In business and research, having complete information allows for better analysis, predictions, and decisions. Without completeness, there is a risk of 'imperfect' decisions due to missing data. These decisions are a part of our daily lives, and even though we rarely have perfect information, we need as much relevant data as possible to make informed choices.