1. What internal control procedure(s) would be most effective in preventing the following errors or fraudulent acts?

a. A programmer obtained the payroll master file and increased his salary.

Some time cards were lost during payroll preparation; consequently, when paychecks were distributed, several employees complained about not being paid.

c. A large portion of the payroll master file was destroyed when the disk pack containing the file was used as a scratch file for another application.