Evaluate each of the following independent situations to determine the type of accounting change (correction of error, change in accounting policy, or change in estimate) and the appropriate accounting treatment (retrospective or prospective). 

a. A building contractor changes from using engineering estimates to the cost-to-cost approach to determine the percentage completed on long-term contracts. 

b. A company’s actuary advises that the expected income from pension plan assets be increased from 4% to 5% per annum. 

c. A clothing retailer switches from using the taxes payable method to the accrual method of accounting for income taxes, which is the same method used by the rest of the industry. 

d. A manufacturing company switches from using the net method to the gross method of presenting government grants, which is the same method used by the majority of its competitors. 

e. A company changes from using the straight-line method to the declining-balance method of depreciating its computer systems.