A club with $x$ members is organized into four committees such that
(1) each member is in exactly two committees,
(2) any two committees have exactly one member in common.
Then $x$ has
(A) exactly two values both between $4$ and $8$
(B) exactly one value and this lies between $4$ and $8$
(C) exactly two values both between $8$ and $16$
(D) exactly one value and this lies between 8 and 16.
Any hints on how to approach this problem ?