Correct answer: (c) ROM
Explanation
- A
REM
Option (a) mentions REM, which is not a standard term for primary non-volatile computer memory. Therefore, this option is incorrect.
- B
RAM
Option (b) refers to RAM, which stands for Random Access Memory and is volatile because its data is lost when power is turned off. Thus, this option does not answer the question.
- C
ROM
Option (c) specifies ROM, standing for Read Only Memory, which retains its contents permanently even when the power supply is completely switched off. This property makes it non-volatile memory, establishing it as the correct key for this question.
- D
None of the above
Option (d) suggests none of the above, which is invalid since ROM correctly identifies the non-volatile computer memory type requested.
Summary. Official key is (c) ROM, which stands for Read Only Memory and securely retains its content without requiring a continuous power supply. Unlike RAM, which clears its data upon shutdown, ROM stores vital bootstrap instructions permanently. Options (a) and (d) are incorrect because they fail to identify a valid non-volatile memory type. Option (b) incorrectly describes RAM, a volatile memory format. Therefore, (c) is the only accurate choice.