The n vertex graph with the maximal number of edges that is still disconnected is a Kn−1
a complete graph Kn−1 with n−1 vertices has $\binom{n-1}{2}$edges, so $\frac{(n-1)(n-2)}{2}$ edges.
Adding any possible edge must connect the graph, so the minimum number of edges needed to guarantee connectivity for an n vertex graph is $\frac{(n-1)(n-2)}{2}$+1
The maximum number of edges to be included in G so that graph is not connected
=$\frac{(n-1)(n-2)}{2}$=$\frac{(99)(98)}{2}$=4851
Hence,Option(C)4851.