Which of the following is a disadvantage of using a singly circular linked list data structure?

Introduction / Context:
Linked lists are fundamental data structures in computer science, and circular linked lists are a useful variation where the last node points back to the first. While circular lists offer advantages such as easy cycling through elements, they also have drawbacks, especially when implemented as singly linked lists with only next pointers. This question focuses on identifying a genuine disadvantage of a singly circular linked list compared to other list structures.

Given Data / Assumptions:

• The list under discussion is a singly circular linked list.
• Each node has at least a data field and a next pointer.
• There is no explicit previous pointer stored in each node.
• We assume standard linked list operations such as traversal and deletion.

Concept / Approach:
In a singly circular linked list, the last node links back to the first node, forming a cycle. Traversal from a given starting node in the forward direction is straightforward using next pointers. However, because there is no previous pointer, you cannot directly move backward from a node to its predecessor. This is similar to the limitation of singly linear linked lists. Deletion of a node given a pointer to that node is not entirely impossible, but it may require special techniques or access to additional information, so the absolute statement in option C is not always correct.

Step-by-Step Solution:
Step 1: Recall the structure of a singly circular linked list, where each node points only to its successor and the last node points to the first.Step 2: Identify typical disadvantages, such as the inability to use next pointers to traverse backward.Step 3: Examine option B, which directly states that you cannot traverse the list backward, which is true.Step 4: Evaluate option C, which claims that deletion from a given node pointer is always impossible, which is an overstatement.Step 5: Conclude that option B alone correctly captures a real disadvantage of singly circular linked lists.

Verification / Alternative check:
You can verify by comparing singly circular lists with doubly linked lists. In a doubly linked list, each node has both next and previous pointers, so backward traversal is possible. In a singly circular list, there is no previous pointer, so you cannot simply move to the preceding node during traversal. This limitation appears regardless of the circular nature of the list and supports the idea that lack of backward traversal is a real disadvantage.

Why Other Options Are Wrong:
Option A describes the presence of an information field in the node, which is not a disadvantage; it is a normal component of any linked list node. Option C is misleading because while deletion from a given node pointer can be tricky, there are techniques to handle it, and the statement that it is always impossible is too strong. Option D combines both B and C, but because C is not entirely correct, option D becomes incorrect as well. Only option B captures a true and unambiguous disadvantage.

Common Pitfalls:
A common pitfall is to treat any difficulty in implementing an operation as an absolute impossibility. For example, deletion from a node pointer in a singly list can be done by copying data from the next node and bypassing it, under some conditions. Another mistake is to forget that the core structural disadvantage compared to doubly linked lists is the lack of backward traversal. Keeping these distinctions clear helps in analyzing data structure trade offs correctly.

Final Answer:
The main disadvantage highlighted here is that You cannot traverse the list backward using the next pointers alone, which corresponds to option B.