—Why do you look so upset?

—There are so many troublesome problems______.

A.remaining to settle                          B.remained settled

C.remaining to be settled                    D.remained to be settled

 --- Why do you look so upset?

   --- There are so many troublesome problems _________.

A. remaining to settle                    B. remained settled

C. remaining to be settled         D. remained to be settled

---Why do you look so upset?

---There are so many troublesome problems _____.

A. remaining to be settled 　　　

B. remained settled

C. remaining to settle 　　　　

D. remained to be settled

---Why do you look so upset?
---There are so many troublesome problems _____.