Answer:
1) loss at disposal                   68,000 debit
   accumulated depreciation 182,000 debit
                  milling machine          250,000 credit
2) loss at disposal                   33,000 debit
    cash                                     35,000 debit
   accumulated depreciation 182,000 debit
                  milling machine          250,000 credit
3) 
    cash                                     68,000 debit
   accumulated depreciation 182,000 debit
                  milling machine          250,000 credit
4) cash                                     80,000 debit
    accumulated depreciation 182,000 debit
    gain  at disposal                          12,000 credit
                  milling machine          250,000 credit
Explanation:
the book value is the same for all alternatives:
cost - accumualted depreciation
250,000 - 182,000 = 68,000 net book value
1) as there is no salvage value all the book alue is considered loss at disposal
from #2 to #4 we recieve cash for the milling machine to determinate the loss/gain we need to do as follows:
 proceeds less book value = result (gain if positive loss if negative)
2)       35,000 - 68,000 = -33,000
3)         68,000 - 68,000 = 0
4)          80,000 - 68,000 = 12,000