Which of the Following Describes Random Assignment in the Context

Multiple Choice

Which of the following describes random assignment in the context of an experiment containing an experimental treatment group and a control group?

A) All participants are assigned to a method of treatment that was randomly selected from ten known treatments in the clinical field. After undergoing treatment, all participants were then placed in the control group.
B) The researcher randomly decides that the first thirty people recruited for the experiment will be assigned to the control group and the next thirty people recruited for the experiment will be assigned to the treatment group.
C) After deciding randomly which condition to start with, the researcher assigned participants alternately to either the control group or the treatment group. That is, if the first participant was assigned to the control group, then the second participant was assigned to the treatment group.
D) Each participant is assigned to either the control group or the treatment group based on a random decision.