Aexperiment is a study designed so that neither the subjects nor the
experimenters know which subjects are in the treatment group and which
ones are in the control group.
o
a. placebo-effect
o
b. control
o
c. double-blind
o
d. biased

Step-by-step explanation:

A double-blind study is a study where neither participants nor experimenters know which subjects are receiving the treatment.

This method is really useful to minimize possible biased conclusions about the experiment.

Therefore, the right answer is C, the situation described refers to a double-blind study.

answer:

c. the third graph