Please answer the following multiple choice questions and provide a written explanation for each answer.

25. A sequential representation of general trees is obtained by the usua.l (left-first, depth-first) traversal of the tree in which every node is visited twice: first a preorder visit, on which occasion the node itself is appended to the sequence representing the tree: and later a postorder visit, on which occasion a special symbol, say )', is appended to the sequence, indicating that the node's child list has come to an end. Using this scheme, the tree E R is represented by the sequence a. A B C) ER)) D) b. A BC)ER) D C. A B C E R D ) d, A ) B ) C ) D ) E ) R) e. A CER) D f A B ) ) C E ) ) R ) D) g. none of the above