Managers at a consumer products company purchased personal computer software from only recognized vendors and prohibited employees from installing nonauthorized software on their personal computers by enforcing a new end-user computing policy. To minimize the likelihood of computer viruses infecting any of its systems, the company should also

a. restore infected systems with authorized versions.

b. recompile infected programs from source code backups.

c. institute program change control procedures.

d. test all new software on a stand-alone personal computer.