In active power and frequency control,a. Frequency should remain constantb. A considerable drop in frequency could result in low magnetizing currents in induction motors and transformers.c. The frequency of a system is dependent on reactive power balance.d. Relatively closed control of frequency ensures constancy of the speed of induction motors.Which of the above statements are incorrect?

• A. a and b
• B. b and c
• C. c and d
• D. a and d