Difference at any instant between the value of the controlled variable and the set point is called the

ANS:A - deviation

The difference at any instant between the value of the controlled variable and the set point is called the deviation. In control systems, the deviation represents the deviation or difference between the actual value of the controlled variable (such as temperature, pressure, or flow rate) and the desired or set point value. It indicates how far the current state of the system is from the desired state. Therefore, the correct term is: deviation.