How many extended partitions can exist on a hard drive?

The correct answer is that only one extended partition can exist on a hard drive. In the Master Boot Record (MBR) partitioning scheme, which is commonly used in older systems, a hard drive can be divided into four primary partitions or three primary partitions and one extended partition. The extended partition is a special type of partition that allows for the creation of multiple logical drives within it, which is necessary since MBR enforces a limit on the number of primary partitions.

This design was implemented to work around the limitations of the MBR structure, enabling users to have more flexibility in organizing their disk space by creating multiple logical partitions within a single extended partition. Therefore, while you can have multiple logical drives inside an extended partition, the hard drive itself can only have one extended partition. This limitation is significant for system design and administration, influencing how storage is managed in operating systems that utilize the MBR partitioning method.