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
Which of the following is a strategy used to increase the yield of protein produced in recombinant protein synthesis ? 
Select and explain. 
A. Promoter induction, B. Genes for protease inhibitors, C. Translation initiation, D. Translation and transcription termination
B: Genes for protease inhibitors
Answer: B: Genes for protease inhibitors 
Explanation: Expression vector is a vector which synthesize the protein coded by a gene introduced via DNA recombination technology. To enhance the final yield of protein product, some expression vectors even contain genes that code for protease inhibitors.