Indicate the nature of each of the situations described below using the following three-letter code. code description cpr: change in principle reported retrospectively cpp: change in principle reported prospectively ces: change in estimate cre: change in reporting entity ppa: prior period adjustment required technological advance that renders worthless a patent with an unamortized cost of $45,000. change from lifo inventory costing to average inventory costing. including in the consolidated financial statements a subsidiary acquired several years earlier that was appropriately not included in previous years. change from fifo inventory method to lifo. pension plan assets for a defined benefit pension plan achieving a rate of return in excess of the amount anticipated. change from the pay-as-you-go method to estimating warranty expense in the period the related product is sold. change from declining balance depreciation to straight-line. change from determining lower of cost or net realizable value for inventories by the individual item approach to the aggregate approach. settling a lawsuit for less than the amount accrued previously as a loss contingency. change in the estimated useful life of office equipment.