A club with $x$ members is organized into four committees such that
Then $x$ has
Answer: $\mathbf B$
This problem can be converted into the graphical form where each nodes represent a committee and the edges represent the member.
So, this problem reduces to nothing but a complete graph. in which each edge can have exactly two nodes(members) or two nodes(members) have exactly one edge(committee).
Hence, $\mathbf B$ is the correct option.