Question

27. In an arbitrary group of six people,
which of the following situations is
impossible?
(A) At least five of them know each
other and two of them do not
know each other,
(B) At least four of them know each
other and three of them do not:
know each other.
(C) No three of them know each
other and no three of them
unknown to each other.
(D) No four of them are unknown
to each other and there is a
person known to every other.
Tiit natural number​

Answer 1

A is the correct answer