490.ZPW-2000A型轨道电路的发送器低频频偏为()。[331010103]

490.ZPW-2000A型轨道电路的发送器低频频偏为()。[331010103]

A.(A)±7Hz

B.(B)±9Hz

C.(C)±11Hz

D.(D)±13Hz

正确答案是C