题目

As smog forced students to stay home, the online learning industry saw a sharp increase in consumers.During the air pollution red alert from Dec. 8 to 10 last winter, the Beijing Commission of Education ordered all kindergartens, primary schools and middle schools to suspend classes (停课). But the commission urged that, Teachers should guide students to make full use of digital materials and conduct online learning at home.According to the China Education and Research Network, the number of new users of 17zuoye. com, an online homework platform, tripled (增至三倍) on Dec. 8 compared to “他活了84岁，一生中的发明有1100项之多，其中最大贡献是发明留声机和自动电报机，实验并改进了白炽灯和电话。”这一生平介绍适用于 [　　] A．西门子 B．爱迪生 C．贝尔 D．哈格里夫斯