The MOST important consideration when selecting a control to mitigate an identified risk is whether:

The most important consideration when selecting a control to mitigate an identified risk is whether the cost of control exceeds the mitigation value, because this determines the cost-benefit ratio of the control. A control should not be implemented if the cost of implementing and maintaining it is higher than the expected benefit of reducing the risk exposure. The other options are not the most important considerations, although they may also influence the control selection process. The availability of internal resources, the potential compounding effects, and the possibility of eliminating the risk are secondary factors that depend on the cost and value of the control. References = CRISC: Certified in Risk & Information Systems Control Sample Questions