Which of the following should a microcontroller at-least should consist of?

مندرجہ ذیل میں سے کون سا مائیکرو کنٹرولر کم از کم ہونا چاہیے؟

CPU, ROM, I/O ports, and timers

RAM, ROM, I/O ports, and timers

CPU, RAM, I/O ports, and timers

CPU, RAM, ROM, I/O ports, and timers

A microcontroller at least consists of a processor as its CPU with RAM, ROM, I/O ports and timers.
It may contain some additional peripherals like ADC, PWM, etc.