This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Surveyor is used on master cast to: 
Select and explain. 
A. Locate guiding planes, B. Determine aesthetics, C. Delineate areas of maximum convexity, D. Locate undercuts to be used for retention or to be blocked out
D: Locate undercuts to be used for retention or to be blocked out
Answer: D: Locate undercuts to be used for retention or to be blocked out 
Explanation: None