See BABOK pg 329 Technique 10.38 Risk Analysis and Management
Risk Assessment: Identifying and evaluating the potential risks associated with each recommendation helps in understanding any uncertainties or potential issues that might affect the success of the recommendations. This can provide valuable insights that might not be immediately apparent when only comparing benefits, costs, and schedules.
Decision-Making: Risks can significantly impact the feasibility and success of the recommendations in the long run. By analyzing the risks, the team can make a more informed decision that considers potential future challenges.
Other options like market research, seeking management guidance, or voting might be useful in different contexts, but they don't directly address the core issue of evaluating the inherent uncertainties between the two equally viable options.