Answer:
c) random assignment.
Step-by-step explanation:
Random assignment -
It refers to the method used for the experimentation purpose , where in a very haphazard manner the task is distributed to the group of objects , participants , human or animal , is referred to as random assignment .
This enables to have a fair participation of all the subjects .
Hence , from the given information of the question ,
The correct option is c) random assignment .