He ordered that the secret message ( ) to the headquarters at

He ordered that the secret message ( ) to the headquarters at once.
A、is sent
B、to be sent
C、be sent
D、being sent
【正确答案】：C
【题目解析】：考核虚拟语气，He ordered that 从句用should +v.或者是v.，句子含义为他命令到，秘密信息立即发往总部。