9.19 During 19X1 and 19X2, Company B used the percentage-of-completion method of accounting for construction. At the beginning of 19X3 it decides to switch to the completed-contract method (for both book and tax purposes). Under this method income before taxes would have been $100,000 lower for both years combined. (a) What type of change is this? (b) What type of approach does this change require: retroactive, or prospective? (c) Prepare the required entry for 19X3. Assume a tax rate for all years of 20%