Assertion (A): Thyristors can be used in controlled heating, excitation systems of alternators, speed control of motors and HVDC Reason (R): A static var system using thyristors is very commonly used in high voltage ac systems.

• Both A and R are correct and R is correct explanation of A
• Both A and R correct but R is not correct explanation of A
• A is correct but R is wrong
• A is wrong but R is correct