In an Experiment Designed to Test Memory Processes, One Group

In an experiment designed to test memory processes, one group was given special instructions and asked to group the items on a list into categories while they tried to memorise them. A second group of participants was given the same list, but they did not receive any special instructions. In this study, the experimental group is

A) the group in which the participants remember the least items from the list.
B) the group who did not receive any special instructions.
C) the group who received the special instructions.
D) the group in which the participants remember the most items from the list.