When explaining the probability of assignment to trial arms in consent forms, which is true?
a. fda requires the probability to be expressed as a percentage chance.
b. the use of a placebo arm does have to be specifically stated, but not the chance of assignment.
c. ich notes that it should be included, but does not specify how the information should be presented.
d. the probability of assignment should always be stated as being "like the flip of a coin" because subjects can understand that example