WG-21A型无绝缘轨道电路自动闭塞(“N+1”系统),发送器空载输出时电源电流( )。[332050203]
A.(A)0.2A~0.3A
B.(B)0.2A~0.35A
C.(C)0.3A~0.5A
D.(D)0.2A~0.5A
正确答案是D