Since the employee has been writing a secure shell around software used to secure executable files and he has also conducted a self-test, he seems to be working in the development environment.
C. Development
Explanation:
The development environment requires an employee to work with algorithms and programming techniques to make programs/software's that are further passed on to the testing department to ensure that they are ready to be launched or deployed.
Although it is the job of testing environment and testers to conduct tests on the developed software's/programs, it is always a good practice to run some self-tests to ensure the efficiency and accountability of a program/software.
