Which of the following is NOT a property of objects used in activities?

The choice indicating 'costly' as a property of objects used in activities is accurate because cost is not inherently a property related to the object's function or characteristics in the context of occupational therapy. In the framework of the Occupational Therapy Practice Framework (OTPF-4), properties such as weight (heavy), visibility (colorful), and safety characteristics (sharp) significantly influence how objects are used in therapeutic activities and interventions. These factors directly relate to the engagement, safety, and effectiveness of activities being performed with clients. In contrast, the cost of an object does not affect its inherent properties or how it can be used within therapy settings, making it less relevant or meaningful in this context. Thus, while objects may vary in cost, it does not pertain to their functional properties during activities.