Final answer:
Hashed files are used in applications requiring timely information, featuring fast data retrieval using hash functions. This makes them ideal for systems where quick access is crucial and exhaustive data processing isn't common.
Step-by-step explanation:
The files that are used mostly in applications where timeliness of information is critical and where data are rarely processed exhaustively are D) Hashed files. Hashed files provide very fast data retrieval for applications that require quick access to records based on specified keys. This efficient access is due to the use of hash tables, which use a hash function to compute an index into an array of buckets or slots from which the desired value can be found. This makes hashed files particularly suitable for databases and indexing systems where performance is a key factor and where the dataset is not typically read sequentially from start to finish.