What does the acronym ROM stand for?

What does the acronym ROM stand for?

• Read online memory
• Random-only memory
• Read-only memory
• Random online memory 

EXPLANATION

Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware (software that is closely tied to specific hardware, and unlikely to need frequent updates) or application software in plug-in cartridges.