Choice "A" is correct. Online, Real-Time (OLRT) Processing is an immediate processing method in which each transaction goes through all processing steps (data entry, data validation, and master file update) before the next transaction is processed. OLRT files are always current, and error detection is immediate.
Choice "d" is incorrect. Batch processing is most often found in traditional high volume transaction processing systems, such as payroll or general ledger. Data may not be current except immediately after all batches have been run.,
Choice "b" is incorrect. Distributed is not a transaction processing mode.
Choice "c" is incorrect. Application is not a transaction processing mode. It typically represents a type of program used by an end user.