How does randomization in an experiment combat response bias?

A. All the subjects that are biased one way get assigned to the treatment group.
B. When subjects are randomly assigned to treatment and control groups, they will not exhibit response bias.
C. In a simple random sample chosen from the population, there will be no response bias.
D. Response bias cannot be eliminated, but it should cancel out between the treatment and control groups.
E. If the experimenter does not know which subjects are in the treatment group, he will not mistakenly cause response bias.

Question

How does randomization in an experiment combat response bias?

 		A.	All the subjects that are biased one way get assigned to the treatment group.
 		B.	When subjects are randomly assigned to treatment and control groups, they will not exhibit response bias.
 		C.	In a simple random sample chosen from the population, there will be no response bias.
 		D.	Response bias cannot be eliminated, but it should cancel out between the treatment and control groups.
 		E.	If the experimenter does not know which subjects are in the treatment group, he will not mistakenly cause response bias.