The situation when in a linked list START=NULL isA underflowB overflowC housefullD saturated

Analyzing the Options

1. Underflow: This term is typically used in the context of data structures such as stacks or queues, where attempting to remove an item from an empty structure causes an error.

2. Overflow: This refers to a condition where a data structure exceeds its maximum limit. In a linked list, this situation does not apply as linked lists can dynamically grow as long as there is available memory.

3. Housefull: This term usually indicates that a venue or storage is full. In the context of a linked list, this is not a applicable term since the list can grow dynamically.

4. Saturated: This term suggests that the resources are fully utilized. For a linked list, a null start does not imply saturation; rather, it implies that no nodes exist in the list.

Conclusion

The correct answer to the problem is A) underflow. When START=NULL, it indicates that the linked list is empty, and any attempt to remove or access elements would lead to an underflow condition.