Answer:
1085° C
Step-by-step explanation:
From the phase diagram of Ag-Cu shown below:
The minimum value of the high-temp required to be selected for the furnace is: 1085° C
This is on the grounds that the furnace should be chosen to such an extent that it should melt any sort of possible material including pure Cu that melts and liquefies at the temperature of 1085° C.