While Both Single-Blind and Double-Blind Procedures Both Prevent a Study

Multiple Choice

While both single-blind and double-blind procedures both prevent a study participant from knowing what a test drug is,single-blind procedures differ from double-blind procedures by:

A) not allowing investigators to know which drug participants received.
B) allowing study participants to later choose which drug.
C) allowing participants in other groups to know which drug they received.
D) allowing investigators to know which drug participants received.