The working papers for a client contain both a permanent and a current file. The difference between the two files is that: 

(a) The permanent file is kept by the audit partner in charge and cannot be altered after the first audit engagement is completed, but the current file can be updated. 

(b) The permanent file is provided to the client and the current file is not. 

(c) The permanent file includes documents that relate to the client and are relevant for more than one audit, and the current file includes the details of work completed and evidence gathered that relate to the current audit. 

(d) All of the above.