\textbf{In the setting of the previous problem, about what percent of the variation in the number of service calls is explained by the linear relation between number of service calls and number of machines?~} 
选项为:A:86\%  B:93\%  C:74\%  D:None of the above  E:\textbf{Can't tell from the information given}  请回答其中一个选项.