Answer

Correct option: (iv) Hard Disk

Explanation

A typical microcontroller integrates essential computing and control resources on a single chip, such as:

• CPU: Executes program instructions.
• RAM: Temporarily stores variables and runtime data.
• I/O ports: Interface with sensors, actuators and external devices.
• Timers/counters: Generate timing functions and count events.
• Peripherals: May include ADC, communication interfaces, PWM and other modules.

A hard disk is a separate mass-storage device and is not normally an integrated component of a microcontroller.

Therefore, the correct answer is (iv).