A.≥20V B.≥21V C.≥22V D.≥23V
A.≥150MΩ B.≥200MΩ C.≥250MΩ D.≥300MΩ
A.2208.4Hz士0.15Hz B.2252.4Hz士0.15Hz C.2298.7Hz士0.15Hz D.2304.5Hz士0.25Hz