I believe the answer is: double-blind experiment
In double blind experiments, the subjects that receive the treatment is remained unknown by both the researchers and the subjects until the experiment is finished. The main purpose of double-blind experiment it eliminate the bias of perception that might exist among researchers.
Answer:
a.option is the correct answer
A locality is a human settlement: city, town, village, or even archaeological site. A place's absolute location is its exact place on Earth, often given in terms of latitude and longitude. For example, the Empire State Building is located at 40.7 degrees north (latitude), 74 degrees west (longitude)
