Perhaps this question may sound silly,and am sorry if there are similar questions answered already because i couldn't find one, as per guidelines. Mask ROM(MROM) are programmed while manufacturing,PROM can be programmed after manufacture and same follows to EPROM and EEPROM similarly how are ROM's are programmed. I assume ROM and MROM are two different things,latter one with program in it loaded while manufacturing. Also if i have wrong concept in my head please make it clear.
I assume ROM and MROM are two different things
You assume incorrectly. "ROM" is just an umbrella term that can be used to refer to any type of memory that cannot be modified after the device has been manufactured. If not otherwise specified, it usually refers to mask ROM, but it can also refer to other technologies which behave the same way, like PROM/EPROM devices or flash memory with writes disabled.