A duty performed by the instructor after administration of a written test is:

The duty of maintaining the security of tests and answer sheets is vital after the administration of a written test. This responsibility ensures the integrity of the testing process by protecting the assessment materials from unauthorized access or tampering. By safeguarding these items, instructors uphold the validity and reliability of the test results, which are crucial for evaluating the students' understanding and learning.

This attention to security helps prevent instances such as sharing questions with future cohorts or compromising the fairness of the testing environment. It supports the principles of academic honesty and fairness, making sure each student is evaluated based on their own merit without any undue advantage or exposure to the test content prior to their assessment.