With reference to her reply to question 421 on 23 March 2016, (a) what were the terms of reference for the investigation undertaken by the Passenger Rail Agency of SA into contracts awarded by its former Chief Executive Officer, Mr. Lucky Montana, (b) on what date did the specified investigation commence, (c) what are the details of the legal processes that determine the envisaged time frames and (d)(i) what budget was allocated for the specified investigation and (ii) what has been spent to date?