Answer:
Balanced placebo design.
Step-by-step explanation:
A balanced placebo design is a type of experimental research design where there are four conditions of treatment – as described in the text above. In this type of design, both drugs and placebo are tested at the same time to check whether the drug is actually affecting the participants as it is intended to. The conditions as described in the text to be experienced by the second and third participant will help the researchers determine the drug’s efficacy.