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
True about precision attachment: 
Select and explain. 
A. One intracoronal preparation in tooth + one integrated into RPD prosthesis to stabilize and / or retain it, B. One intracoronal preparation in tooth + one removable attachment to prosthesis, C. One intracoronal fixed on abutment + one integrated into RPD prosthesis to stabilize and / or retain it, D. All of the above
C: One intracoronal fixed on abutment + one integrated into RPD prosthesis to stabilize and / or retain it
Answer: C: One intracoronal fixed on abutment + one integrated into RPD prosthesis to stabilize and / or retain it 
Explanation: Internal attachment / precision attachment - Means interlocking device, one component of fixed into an abutment or abutments + other integrated to a removable prosthesis to stabilize and/or retain it
Semipresicion rest- Rigid metallic extension of a fixed or RPD + fits into an intracoronal preparation in a cast restoration.