Why did the us commissioners agree to postpone treaty making during the fort smith council? a. to allow more delegates to come to the council b. to let delegates from other tribes attend the council c. to move the council to washington, away from indian territory d. to wait until the five tribes resolved their internal conflicts  its c

The correct option is C.
The Forth Smith Council is a series of meetings, which the US federal government representatives had with the native American tribes in September, 1865, it was organised by the commissioner for Indians Affair. At the end of the meeting, the commissioner had to adjourned the meeting to a later date and it was agreed that the delegation will later meet at Washington DC in early 1866 to complete the treaties. 

The answer is option b and c.