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: Biochemistry
Sequence which is responsible for retaining proteins in membrane 
Select and explain. 
A. Translocon, B. Sec 61 complex, C. Docking protein, D. Halt signal
D: Halt signal
Answer: D: Halt signal 
Explanation: D i.e. Halt signal