Indians always shake (摇) their heads when

问题：

Indians always shake (摇) their heads when they talk to others. (41) does not have the same meaning (42) "no". If someone wants to visit India, (43) should know this, (44) it will give him some trouble.
One day, a foreign officer went to India on business. He hired (雇佣) a car and an Indian to drive it. When he (45) the driver to send him to his office, the driver shook his (46) at once. The officer repeated his order, and the driver (47) so again. At last, the officer, of course, got (48) .
" (49) dare you refuse (拒绝) my order" he shouted. "Drive me to office immediately!"
The driver answered (50) quite a loud voice, too. "Yes, sir !" But he still shook his head at the same time. Suddenly the officer realized that, "No means Yes here!\

[A] you[B] he [C] they