Final answer:
ROM access time is defined as the time it takes to get valid output data after a valid address is applied. It is an indicator of how quickly data can be read from ROM, impacting the system's performance.
Step-by-step explanation:
ROM access time is defined as the time it takes to get valid output data after a valid address is applied. This is a measure of how quickly a ROM can provide data after the memory address has been specified. ROM is a type of non-volatile memory, which means it does not lose the stored information when power is turned off. ROM access time is essential for understanding the performance of the ROM and how it can affect the overall speed of a computer system.
Option B, the difference between the READ and WRITE times, is not applicable because ROM is typically read-only and does not have WRITE times. Option C, how long it takes to program the ROM chip, relates more to the initial creation or updating of the ROM content, which is not frequently done. Finally, option D, the time required to activate the address lines after the ENABLE line is at a valid level, describes the operation of the address lines' enable signal, not the access time.