A three-phase synchronous generator runs stably under a symmetrical load(
A、Straight-axis magnetic armature reflection;
B、There are both straight-axis demagnetic armature reaction and cross-axis armature reaction;
C、There are both straight-axis magnetic armature reactions and cross-axis armature reactions;
D、There are both straight-axis armature reactions (demagnetization, magnetism-assistant) and cross-axis armature reactions.