What kind of memory loses its contents when the power is turned off?

The correct answer is RAM, which stands for Random Access Memory. This type of memory is volatile, meaning that it temporarily stores data and is used for tasks that require quick access to information. Once the power is turned off, RAM loses all of its stored data because it needs a continuous power supply to maintain the information.

In contrast, ROM (Read-Only Memory) retains data even when the power is off, as it is non-volatile. Flash memory also retains data without power and is commonly used in USB drives and SSDs. Hard drive storage, whether it's traditional spinning disks (HDDs) or solid-state drives (SSDs), is designed to keep data intact even without power, making them suitable for long-term storage. Thus, RAM is the only memory type among the choices listed that loses its contents when power is turned off.