Assertion (A): A synchro control transformer has nearly constant impedance across its rotor terminals.Reason (R): Rotor of a synchro control transformer is cylindrical so as to give uniform flux distribution.

• A. Both A and R are correct and R is correct explanation of A
• B. Both A and R are correct but R is not correct explanation of A
• C. A is correct but R is wrong
• D. R is correct but A is wrong