Presented below are a number of operational guidelines and practices that have developed over time. Select the assumption, principle, or constraint that most appropriately justifies these procedures and practices. (Do not use qualitative characteristics.) (a) (b) (c) (d) Intangible assets are capitalized and amortized over periods benefited. Brokerage firms use fair value for purposes of valuing investments. Each enterprise is kept as a unit distinct from its owner or owners. All significant post-balance-sheet events are reported. Fair value changes of fixed assets are not recognized in the accounting records. Supplemental information is presented so that investors will not be misled. Revenue is recorded at point of sale. (e) () (8) (h) All important aspects of bond indentures are presented in financial statements. Rationale for accrual accounting. (1) (1) (k) The use of consolidated statements is justified. Reporting must be done at defined time intervals. An allowance for doubtful accounts is established. (1)