The Original Depreciation or Amortization Schedule for Long-Lived Assets Sometimes

The original depreciation or amortization schedule for long-lived assets sometimes requires changing.Which of the following is/are not true?

A) Each period a firm must evaluate its estimates of service life and assess if these estimates require changing in light of new information.
B) Each period a firm must evaluate its estimates of salvage value and assess if these estimates require changing in light of new information.
C) The firm makes no adjustment for the inaccurate estimates but spreads the remaining carrying value less the new estimate of salvage value over the new estimate of the remaining service life of the asset.
D) If changing from the old estimates to the new estimates would have a material impact, the firm must change the depreciation or amortization schedule retroactively.
E) none of the above