A Protein with Five Disulfide Bonds Was Treated With $\beta$ -Mercaptoethanol and Urea

Multiple Choice

A protein with five disulfide bonds was treated with $\beta$ -mercaptoethanol and urea. Once the protein was denatured, the $\beta$ -mercaptoethanol and urea were removed by dialysis. What is the likelihood that all five disulfide bonds will reform correctly?

A) 1/5 or 20%
B) 1/10 or 10%
C) 1/10² or 4%
D) 1/5! = 1/120 or 0.83%
E) 1/945 or 0.11%