—Is there any possible way to help them get rid of such a bad habit?

—To tell the truth, it’s very hard. But we ________ on this problem, trying to improve the situation .

A．worked

B．had worked

C．are working

D．had been working

在进行餐厅员工人数设定时须考虑的因素是下列哪项（）？

A.酒店房间的数量和客房营业额

B.酒店餐厅的供应形式和客源

C.酒店餐厅的餐位数量和客源

D.酒店餐厅的营业额和供应形式