Select the correct alternative from the given choices.
An undirected graph $G$ has ' $n$ ' nodes. Its adjacency matrix is given by an $n \times n$ square matrix.
(i) Diagonal elements are 0 's
(ii) Non-diagonal elements are l's
Which of the following is true?
(A) Graph $G$ has no minimum spanning tree
(B) Graph $G$ has a unique minimum spanning tree of $\operatorname{cost}(n-1)$
(C) Graph $G$ has multiple distinct minimum spanning trees, each of cost $(n-1)$
(D) Graph $G$ has multiple spanning trees of different cost.