Fields are said to be circularly polarized if

A)
their magnitudes are equal
B)
their magnitudes are unequal and they are in phase
C)
their magnitudes are unequal and they differ in phase ± 90°
D)
their magnitudes are equal and they differ in phase by ± 90°

Correct Answer : Option (D) :   their magnitudes are equal and they differ in phase by ± 90°