问题

It’s no easy task to catch a ticket on awebsite that receives l billion clicks daily__I can’tagree with you moreTherebe errors for every single step
A:to blame; occurred
B:to blame; occurring
C:to be blamed; occurred
D:to be blamed; occurring
B:to blame; occurring
C:to be blamed; occurred
D:to be blamed; occurring
正确答案是: