Which of the following is the MOST important factor when deciding on a control to...

 The most important factor when deciding on a control to mitigate risk exposure is the cost-benefit analysis. This is a process that compares the costs and benefits of implementing a control, and determines whether the control is worth the investment. A cost-benefit analysis helps to ensure that the control is efficient and effective in reducing the risk to an acceptable level, and that it does not introduce new risks or adversely affect other objectives. A cost-benefit analysis also helps to prioritize the controls based on their value and feasibility, and to allocate the resources accordingly. References = Risk and Information Systems Control Study Manual, 7th Edition, Chapter 4, Section 4.2.5, page 1861