The expected answers were:

(a)      An open loop control system is one in which the control actions is independent of the output while a closed loop control system is one in which the control action is somehow dependent on the output.

Classification:

Open loop	Closed loop
Operating a toggle switch	Traffic light controller
Traffic light controller	Bread toaster
	Bicycle-riding process

(i) Positive feedback

(ii) Feedback factor with magnitude of unity (1)
(iii) Feedback factor with a phase of 1800

The question was on Control Circuits. The question was unpopular. The performance of the very few candidates that attempted it was reportedly poor.