In linked list implementation of queue, if only front pointer is maintained, which of the following operation take worst case linear time?

In a linked list implementation of a queue, if only a front pointer is maintained, the operation that takes worst case linear time is the 'dequeue' operation.

Here's why:

1. In a queue, the 'dequeue' operation involves removing an element from the front of the queue. If we only have a front pointer, this operation can be done in constant time, because we can directly access the front element.

2. However, after removing the front element, we need to update the front pointer to point to the next element in the queue. If we only have a front pointer, we have no direct way of knowing what the next element is.

3. Therefore, to update the front pointer, we would need to start from the front of the queue and traverse the linked list until we find the next element. This traversal takes linear time in the worst case, because we may need to traverse all the elements in the queue.

4. Hence, if only a front pointer is maintained in a linked list implementation of a queue, the 'dequeue' operation takes worst case linear time.