C. effort costs (the costs of paying software engineers and managers)
D. all of the mentioned
✅ The correct answer is option D.
Explanation: Estimation involves working out how much effort is required to complete each activity and, from this, calculating the total cost of activities.
✅ The correct answer is option D.
Explanation: Active Participation of user is involved in all the four phases of RAD model and in case of the Prototyping model we need user’s presence/involvement every time a new prototype is build or designed.