Identify the internal control principle that was violated in each of the following separate situations.

$\backslash$table$[[$Situations$,],[$a$.$ An employee requested merchandise be purchased, then approved the purchase request, and finally made payment to a$,],[$fake supplier. The employee stole a considerable amount of money under this scheme.,$],[$b$.$ A disgruntled employee stole expensive equipment from a room they were unauthorized to enter. The room displayed a$,],[$sign$,$ "Authorized Employees Only," but did not include any physical locks or ID scanners to limit access.,$],[\backslash$table$[[$c$.$ As a result of significant internal control weaknesses, the company lost millions and was forced to close. Two years prior,$],[$the company stopped paying for regular audits of internal control to save for renovations of executive offices.$]],]]$