单项选择题下列哪个句子最符合科技英语写作规范? A、The loudspeaker, an electroacoustic transducer, converts audio-frequency power into acoustic power. B、The loudspeaker; an electroacoustic transducer; converts audio-frequency power into acoustic power. C、The loudspeaker—an electroacoustic transducer, converts audio-frequency power into acoustic power.