'Participant Observation' Is Different from Other Forms of Observation in That

'Participant observation' is different from other forms of observation in that:

A) it focuses on individual participants, instead of the group.
B) the observer participates in the culture under study.
C) the observer actively manipulates the environment of those she observes in order to test hypotheses.
D) the observer maintains a certain amount of proximity to the people she tries to observe.
E) it does not take place in a laboratory.