Explanation:
A complete binary tree is a binary tree in which all the levels except the last level are completely filled and all the nodes are left-justified. In a complete binary tree, the nodes are filled from left to right in each level.

Inorder Traversal:
In inorder traversal, the left subtree is visited first, followed by the root node, and then the right subtree. In a complete binary tree, if we perform an inorder traversal, the left subtree will be visited first, followed by the root node, and then the right subtree. However, since the nodes are filled from left to right in each level, the inorder traversal will not produce the data in sorted order. Therefore, option (b) is not correct.

Preorder Traversal:
In preorder traversal, the root node is visited first, followed by the left subtree, and then the right subtree. In a complete binary tree, if we perform a preorder traversal, the root node will be visited first, followed by the left subtree, and then the right subtree. However, since the nodes are filled from left to right in each level, the preorder traversal will not produce the data in sorted order. Therefore, option (a) is not correct.

Postorder Traversal:
In postorder traversal, the left subtree is visited first, followed by the right subtree, and then the root node. In a complete binary tree, if we perform a postorder traversal, the left subtree will be visited first, followed by the right subtree, and then the root node. However, since the nodes are filled from left to right in each level, the postorder traversal will not produce the data in sorted order. Therefore, option (c) is not correct.

Level Order Traversal:
In level order traversal, the nodes are visited level by level, from left to right. In a complete binary tree, if we perform a level order traversal, the nodes will be visited in the order in which they appear in the array representation. Since the array representation of a complete binary tree contains the data in sorted order, the level order traversal will produce the data in sorted form. Therefore, option (d) is correct.