An IS auditor discovers that developers have operator access to the command line of a production environment operating system. Which of the following controls would BEST mitigate the risk of undetected and unauthorized program changes to the production environment?

A. Commands typed on the command line are logged
B. Hash keys are calculated periodically for programs and matched against hash keys calculated for the most recent authorized versions of the programs
C. Access to the operating system command line is granted through an access restriction tool with preapproved rights
D. Software development tools and compilers have been removed from the production environment