Final answer:
The answer to the students' question is C. An organization would not restrict bids to a single vendor to improve its bargaining position by maintaining a competitive selection posture; this implies seeking multiple bids for better bargaining.
Step-by-step explanation:
An organization might request bids for computer resources from only one vendor for all of the following reasons except to improve its bargaining position by maintaining a competitive selection posture. The valid reasons for an organization to stay with a single vendor include reducing training costs, satisfying specialized needs, and minimizing conversion costs. Each of these reasons has to do with loyalty to a current vendor or specific requirements that only a single vendor can fulfill.
Option C, however, suggests a scenario in which a company would want to keep options open and encourage competition among various vendors to improve its bargaining power, which contradicts the premise of sticking with a single vendor. Competitive selection posture implies seeking multiple bids to create a competitive environment that could potentially lead to better pricing or terms, not limiting the bid to one vendor.