Заполните пропуски в предложении.He asked us since early morning? We

Заполните пропуски в предложении.
He asked us since early morning? We answered that we for the examination.
Изберите один ответ:
а)what you have been doing there, have prepared
б)what had you been doing here, have been preparing
в)what we had been doing there, had been preparing
г)what have you been doing here, had prepared