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
Main objective of Tweed's analysis: 
Select and explain. 
A. Determination of the position of lower incisors and evaluation of prognosis of a case., B. Profile of an individual, C. Relationship between maxillary central and mandibular central incisors, D. The position of maxilla and mandible to each other
A: Determination of the position of lower incisors and evaluation of prognosis of a case.
Answer: A: Determination of the position of lower incisors and evaluation of prognosis of a case. 
Explanation: The main objective of Tweed's analysis includes the determination of the position of lower incisor and evaluation of the prognosis of a case. The angles in Tweed's analysis are FMIA, IMPA and FMPA.
Incisor mandibular plane angle (IMPA) is the angle between long axis of lower incisor with the mandibular plane. The mean value is 90°. It indicates the inclination of lower incisor.