Computer memory is any physical device, used to store data, information, or instruction temporarily or permanently. It is the collection of storage units that stores binary information in the form of bits. There are four major storage levels. Internal memory for example cache. Cache memoryIt is a small-sized type of volatile computer memory that provides high-speed data access to a processor and stores frequently used computer programs, applications, and data. It is the fastest memory in a computer,Main memory like RAM and controller cards. Main memory is used to keep programs or data when the processor is active to use them. Random Access Memory (RAM) is one of the faster types of main memory accessed directly by the CPU. It is the hardware in a computer device to temporarily store data, programs, or program results. It is used to read/write data in memory until the machine is working. Online mass storage or Secondary storage like Solid-state driveSolid-state drive:it is a non-volatile storage device, which stands for Solid State Drive. SSD stores the data on flash memory chips and maintains the data in a permanent state, even when the power is off. As of 2017, the best access speed is from a consumer solid-state drive is about 2000 MB/sIt is faster than tertiary storage devices. Off-line bulk storage or Tertiary storage like Optica drive An optical drive is an internal or external computer disk drive that uses laser beam technology to read and write data. For example CDs and DVDsAccess speed is 150 millisecondsThus we conclude that the correct answer is (C), (A), (D), (B)