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
Intracoronal retainer placed in the abutment teeth has the following disadvantage 
Select and explain. 
A. It is unaesthetic, B. They cannot provide support and stability, C. Difficult laboratory procedure, D. Difficult to repair and replace
D: Difficult to repair and replace
Answer: D: Difficult to repair and replace 
Explanation: Internal or precision attachments
Advantages:

Improved aesthetics, by elimination of a visible retentive component and vertical support.

Disadvantages:

Difficulty in repair and replacing.
Greater cost to the patient.
Inability to use in teeth having short clinical crowns and tissue-supported distal extension denture bases.