"Zero Acquaintance" Is Best Described as What

"Zero acquaintance" is best described as what?

A) Observing someone who is not related to the observer
B) Observing someone while they socialize with people he/she has never met before
C) Observing someone who has had little interaction with the observer
D) Observing someone who has never interacted with the observer
E) Observing someone who has no friends or acquaintances