Select the correct alternative from the given choices.
Which of the following statements are true?
(i) Any graph which contains some parallel edges is called a multigraph.
(ii) An edge of a graph which joins a node to itself is called a self-loop.
(iii) If there is no more than one edge between a pair of nodes, then such a graph is called simple-graph.
(iv) In a digraph, every edge is directed with an ordered pair.
(A) Only (i), (ii) and (iv) are correct
(B) Only (iii) and (iv) are correct
(C) Only (i) and (iii) are correct
(D) All are correct